Pioneering Women in Physics - IOP event

On the 4th March, a few of us graduates took the day off work and took a trip to London to the all-day Institute of Physics event ‘The Lives and Times of Pioneering Women in Physics. It was such a fun and inspiring day so I’ve put together some highlights. The first one is of course that we got to meet grand-daughter of Marie Curie – Hélène Langevin-Joliot, who has been a nuclear physicist herself. She told us some lovely personal accounts of her grand-mother’s life. We made sure to get a picture with her:

Grand-Daughter of Marie Curie (middle) with (from left to right) Alex, Katy, Ailsa and Sarah

 

As soon as we arrived at the IOP building, we noticed that all of the rooms are named after inspirational female physicists, and instead of seeing lots of typically-male pictures of Nobel-prize winners dawning the walls, we saw lots of pictures of female physicists! It seems that the Women in Physics group have a large influence.

After coffee and biscuits the talks began with an introduction from Professor Edward Davis, Chairman of the History of Physics Group, who generated gasps of disbelief from the audience when describing a newspaper article from the previous day which described an incident in an all-boys school where a pupil had said – “Women shouldn’t be in science, they should stay in the kitchen” to a female lab-technician.  Heather Williams then greeted us and prepared us for a day with the aim “…to see how far we’ve come, and how far we need to go”. I’m going to give some of the highlights of each talk, and it’s my interpretation – so don’t quote the speakers on it!

 

Order of speakers (click on links):

 

The contribution of women to physics: a historical perspective

Dr Gillian Butcher
Grand-daughter of Marie Curie  - Marie Curie (1867 – 1934): Pioneer of Radioactivity
Prof Hélène Langevin-Joliot

Lise Meitner (1878-1968): Pioneer of nuclear fission
Prof Gerry Lander

Mary Somerville and her work in astronomy and optics, c 1820-1991
Prof Allan Chapman

Edith Stoney (1869 – 1938) : Pioneer of medical physics
Prof Francis Duck

The first female physics professors in the UK, Daphne Jackson (1936-1991) and Gillian Gehring
Prof Gillian Gehring

Women in Crystallography
Dr Kate Crennell
History’s Lessons: opportunities and challenges for women in physics today.
Dr Heather Williams

 

Dr Gillian Butcher - The contribution of women to physics: a historical perspective
When Dr Butcher told us that the first mention of a female ‘scientist ‘ was in about 2700BC in Egypt, we knew we were in for a truly historical overview. This Egyptian woman was called a chief physician. However by the time Hippocrates came around in 460-370BC, he claimed that the cause of women’s health problems and emotional instability was a ‘wandering uterus’ – which we didn’t think our Egyptian Chief Physician would agree with… There are also various mentions of women scientists in Ancient Greece, and some doing Alchemy (which was classed as science) in Alexandria.

In the Middle Ages, there was not much science going on in Europe in general, but in China, India and Arab countries, universities were beginning to be founded, and the scientific method was making an appearance. Most of the mentions of female scientists in this period are from convents, such as the famous Hildegarde of Bingen who produced scientific and medicinal writings.

Elsewhere in Europe, Italy had female students and staff, and in England there were female surgeons by the 16th Century.  However, women were more often than not getting punished for having knowledge, as shown by the life imprisonment of the Duchess of Gloucester, Eleanor Cobham, who was accused of witchcraft.  This fear of women’s intellect and sexuality had grown by the time of the Restoration in 1660, when there were many more witch trials. During the civil war the Diggers (or Levellers) argued for absolute equality for women, but the industrialisation of the country started to divide gender roles even more.
Science was progressing though, and Francis Bacon was leading the way, however he didn’t have much of an opinion of women as shown by this quote “Science is mastery of man over nature, nature as the bride is seduced, conquered and stripped of power”. The Royal Society in 1612 was more like a private Gentleman’s club. Opportunities for women in science mainly lay with middle and upper classes who could afford technology such as the telescope, microscope and printer. In 1694 Mary Astell published the lovely book below, arguing for women’s education.

 

In the 17th and 18th Century, more and more women were beginning to play a role in science, especially in Italy; however they were all from wealthy families, and only ever assistants to men.

In the 18th Century we see the rise of professional science, it becomes more restricted, women are not allowed, neither are those of the ‘wrong’ religion or class. Only in the 19th Century do we start to see more women scientists, Marie Curie, Annie Jump Cannon and Lise Meitner. In the 1870s and 1880s women were being admitted to Oxbridge and by 1919 Oxford started to allow women onto degree courses. By 1920, 14% of those earning doctorates in physical and biological science were women, however by  1960 that had reduced to 5%. At the moment we have about 15% women studying for doctorates in just physics. This shows that it’s not a linear process; it depends so much on time, location, religion and many more factors (to be explored later).
Dr Butcher took us on a whirlwind-tour of the history of women in science, and ended on a quote from Rachel Ivie from the American Institute of Physics “Even if I tried not to choose physics – it would choose me”.

 

Professor Gerry Lander – Lise Meitner (1878-1968): Pioneer of nuclear fission

Professor Lander gave a nice overview of Lise Meitner’s work and life; he started off with what is written on her gravestone “A physicist who never lost her humanity”.  She had a very difficult career, having to deal with many prejudices and barriers. When she first started her job in Berlin she was not even allowed in the front door of the university, she had to go in the back entrance. Being Jewish, she also faced difficulties being in Nazi Germany and had to escape in 1938. She was still in contact with Hahn, her previous supervisor, who had detected (what he thought was) radium for the first time after bombarding uranium with neutrons.  Living in Copenhagen and working with Bohr, they persuaded Hahn to check the chemistry of the radium and he discovered that it wasn’t radium at all, and was actually barium. Meitner and her nephew Frisch, also a physicist, took a walk in the woods and whilst talking about this discovery realised that the cause must have been nuclear fission. They published this discovery in Nature, but took too long, and Hahn had already published his paper using the term fission. It was soon after this that the Manhatten Project was started.  Meitner was asked to work on it but refused, and was horrified after Hiroshima. In 1945 it was announced that the Chemistry Nobel Prize was going to Hahn alone, which is generally considered a great injustice. Hahn never acknowledged Meitner publically but did share the prize money with her.

Lise Meitner - Pioneer of nuclear fission

 

Professor Hélène Langevin-Joliot, Grand-daughter of Marie Curie  - Marie Curie (1867 – 1934): Pioneer of Radioactivity
Before Professor Langevin-Joliot’s talk we learned that they have 5 Nobel prizes in their extended family! Professor Langevin-Joliot gave a lovely personal account of Marie Curie’s life which was amazing to hear first-hand. She affectionately called her ‘Marie’ for the talk so I will too! Marie had a very difficult life, but had a huge love of science, she worked very hard for her achievements and said once “I have a sort of hope that I shall not disappear…into nothingness”. She was considered ‘just an assistant’ to her husband for a very long time.
Marie and Pierre met in 1895, just when she had been given a grant for her research and Pierre was to help. After one afternoon of talking about physics with Marie, he apparently changed his mind about women and fell in love. Pierre wanted to get married, but Marie had to go home, and he convinced her to return by his letters. She ‘chose Pierre and the Scientific Dream’. They had very different personalities – ‘Pierre was as dreamy as Marie was organised’, but they had the same dream about society. They were married in the same year they met and Marie was allowed to work at the school where Pierre was a professor. In 1897 they had their first daughter (Professor Langevin-Joliot’s mother). They were doing research into a ‘spontaneous reaction’, which was very surprising and unexplained at the time. Becquerel had given up trying to find the cause of this, but Marie had persevered, looking at other materials for similar behaviours (e.g. Thorium). It was her decision to investigate the mineral Pitchblende (uraninite) which led to the discovery of radium. She signed the paper and coined the term ‘radioactive’, but Pierre got the prize in the end…  They continued their huge success working in ‘The Shed’ – their lab, until Pierre tragically died in 1906. In Professor Langevin-Joliot’s words ‘it broke her life’. Marie took over from Pierre and became the director of the lab, the first woman in this role. A feminist victory, but Marie was very depressed, and was still writing to Pierre – ‘some fools congratulated me’ on her new job.
She finally got the Nobel Prize in Chemistry in 1911 for the discovery of polonium (named after her country of birth).  She claimed the two most important qualities for success are self-confidence and diplomacy. After that Marie became more interested in the medical application of her discoveries, as Pierre had been. She travelled to America in 1921 to set up “The Curie Foundation”, and she became vice-chair of the International Committee for Intellectual Cooperation. In a letter to her daughter she said “I have given a great deal of time to science because I wanted to, because I loved research”. She has become a mythic figure, and caused a shift in the field of nuclear physics. So many outstanding achievements for an outstanding woman, who overcame many struggles.

Marie-Curie - Pioneer of radioactivity

 

Professor Allan Chapman - Mary Somerville and her work in astronomy and optics, c 1820-1991.
Allan Chapman, a prominent historian (just look at his Wikipedia page!) has written an entire book on Mary Somerville, so he knows his stuff. He gave a hugely entertaining and very interesting talk. We got an instant feeling about what kind of person Mary Somerville was with Professor Chapman’s first fact – she lived for 92 years and died correcting proofs at her desk! We also learned that she was a big character with a ‘racy tongue’, she was ‘no prude!’ and ‘could swear like a British trooper’. Basically she had a tremendous personality, was a strong feminist and from a young age was fascinated by the strange symbols in maths textbooks. Her father thought that reading these books would soften her brain so he confiscated the books, but she memorized the pages. Her first husband had similar opinions, but when he died, she was still in her late 20s and started to pay for private classes in physics and maths (since she wasn’t allowed to attend university). She became bored with the maths of the UK – it seemed to her to be behind it’s game, so she bought books from France by Euler and Laplace and started corresponding with them, and started to get interested in crystallography and astronomy.
Luckily her second husband encouraged her intellect and was actively proud of her pursuits. By then it was the end of the Napoleonic wars and suddenly she had the option to visit France. It turned out she was already quite famous there from her correspondences, even considered one of England’s finest mathematicians. Her husband William became a fellow of the Royal Society and Mary subsequently met Faraday and Herschel and soon started doing research. She published the first paper by a woman in the Phil.Trans journal and went onto write several more distinguished pieces. At age 90, she was living in Italy and her Nephew comes along with an ironclad battleship. She was so curious that she went to visit and boarded it, insisting that they fire the guns for her!
Professor Chapman finished his talk by showing us a picture he has drawn of her telescope, which they are reconstructing for Somerville College in Oxford. She was and still is an inspiration to many women; they have even named a crater of the moon after her!

Mary Somerville

 

Professor Francis Duck - Edith Stoney (1869 – 1938) : Pioneer of medical physics

When Edith Stoney wanted to attend university, having already been privately educated, she had limited options. The local Dublin universities did not accept women, so she went to the Royal College of Science for Ireland, science was the only option.  By the time she had finished her studies there, Cambridge was accepting women but not issuing them degrees, but she went to study maths there. She then became a maths teacher at Chaltenham Ladies College and then a physics lecturer at London School of Medicine for Women where “her lectures mostly developed into informal talks”.
England was particularly slow at that time to realise how important physics was to medicine. Edith and her sister Florence were pioneers of medical physics and set up the first radiology service at the Royal Free Hospital. Edith was a suffragette and political activist. When war broke out Edith and Florence offered to go to the front line with their equipment but were rejected. Florence went anyway with the Women’s Imperial Service League and got an OBE for her efforts.  Edith joined the Scottish Women’s hospitals through the Suffragists. She ran X-Ray services under the French Red Cross. They had a hard time during the war, Edith was working in Serbia, changing gas in the X-ray tubes, treating gangrene and foreign bodies, doing electric bath treatments. Of course, there was no radiation protection then, and the women were getting radiation burns.
In all of the reports from the time she is judged for her appearance rather than being praised for her knowledge and skills “Grey uniform, grey hair, pale blue eyes”, “a mere wraith of a woman”. Edith earned herself 5 war medals in the end. At the end of the war she got a lectureship at Kings College, she could not get a medical physics job since she had no formal qualifications. In her retirement, she studied the effects of UV and vitamin D on osteomalacia. The first woman in medical physics, and a physicist to the end.

Edith Stoney - Pioneer of medical physics

 

Professor Gillian Gehring – The first female physics professors in the UK, Daphne Jackson (1936-1991) and Gillian Gehring
The next speaker was a true role model for physicists everywhere. Gillian Gehring, you just have to read her blurb on the University of Sheffield’s webpage . The second ever woman in the UK to hold a professorship, and talking about her mentor Daphne Jackson, who was the first. I was particularly inspired by Professor Gehring and her subject, because not only was she talking about two physicists with very important and interesting research, but also who have taken hugely important steps to help women stay in physics, while allowing them to have a family life as well.
Daphne Jackson was the first female professor at the young age of 36, and the youngest ever IOP fellow. Almost half of her papers were on science on society, and most of the rest on medical physics. She was always concerned about the lack of women in physics and called it ‘an appalling waste of talent’. Her own experience of caring for her own mother with dementia, and getting no support from social services spurred her onto setup the ‘Women Returners to Science and Engineering’ Fellowship, and this turned into Daphne’s hobby. She hoped it would be taken over by a public body. She lobbied, wrote articles, raised £400,000 from donors and got 132 applicants. The idea is that the selected fellow works part-time for 2-3 years and undergoes a re-training programme, allowing them to gradually enter back into their professions. Daphne took a major role and acted as a councillor to the follows. Unfortunately Professor Jackson died young, aged 54, she had tragically and ironically contracted Breast cancer while studying it. Now her legacy lives on however, and is now called the ‘Daphne Jackson Trust’ and has helped over 250 women restart their careers, and now also helps men as well. Gillian still helps with the trust, which struggles to get enough funding for the number of suitable applicants. Hearing Dr Gehrings enthusiasm on the scheme, and hear her talk about this amazing friend of hers who set it up was really inspiring.

 

Daphne Jackson

Dr Kate Crennell: Women in Crystallography

Dr Crennell, a crystallographer herself gave a nice overview of various women in crystallography. She set up a biographical website for these women which gives a nice historical overview of their lives and works . We learned about the pioneers of crystallography – Dorothy Hodgkin, Rosalind Franklin, Kathleen Lonsdale, Helen Megaw, and Louise Johnson.  Rosalind Franklin did breakthrough work on the structure of DNA, and may have just missed out on the Nobel Prize if she hadn’t passed away so young (aged 37). Instead Crick, Watson and Wilkins (who worked in the same laboratory as Franklin- and who allegedly showed Crick and Watson her data before she had published it), were awarded it in 1962.
Kathleen Lonsdale- “Housewife, mother, Quaker, scientist and teacher” was so promising to Bragg, that he found her funding for childcare so he could do research with her (we need more of that now!).  She famously discovered that the Benzene ring was planar. She was a strong pacifist and when the war broke out she refused to pay her fine for not doing civil defence duties and went to prison for a month. One structure of diamond is named after her ‘Lonsdaleite’.
Dorothy Hodgkin, a student of Somerville college, and who supervised Margaret Thatcher, was the first woman to be awarded a Nobel prize. She was also president of the Pugwash organisation (physicists for peace) – another pacifist like Lonsdale.

 

Dr Heather Williams – History’s Lessons: opportunities and challenges for women in physics today
Dr Williams, co-founder and director of ScienceGrrl gave an informative evidence-based talk (just what we scientists like!) – pointing out that we’ve come a long way, but there is still a long way to go. She started by highlighting that the lack of women in science is actually a culturally specific problem – the numbers of women in science roles varies hugely country to country.
All of the data she gave however, showed fewer than 50% women in science in each country. Interestingly, the number of women doing science subjects at GCSE is approximately 50%, but as soon as you look at A-Level students, it drops to about 25%, which stays approximately constant when you go to Undergraduate and Postgraduate. Then you hit Researcher and it starts to drop, again for Lecturer positions, and by the time you get to professor level it’s shockingly only about 5% women. There is a similar trend in all subjects, although the baseline is higher (~50% at the beginning, dropping down to ~20%). 
Heather highlighted some of the issues affecting women as they progress in their careers, including gender expectations in relation to child care and housework, lack of affordable childcare or flexible working arrangements, difficulties in progression after periods off from work , job insecurity, the ‘two-body problem’ (explained very nicely here),  and unconscious bias. She showed the figures for % of female entry into A –level subjects. The lowest was computing at a mere 7%, physics was 21%, maths at 39%. The highest were performing arts (88%), art and design (75%), psychology (74%).  However, interestingly Heather showed some figures showing that once females have decided on a science subject they tend to stay in that field, but fewer of them finish their degrees it seems.
Heather then went back to the problem of culture and showed some examples of the terrible gender stereotyping that crop up all over the place in our society. She also highlighted the huge impact these seemingly trivial gender biased toys, confectionary, cards, books, journalism (etc) have with a  quote from Gina Rippon, Professor of Cognitive Imaging at Aston University –“ The brain is much more plastic than early neuroscientists ever dreamed, it is hugely  permeable to society’s influences. Life’s experiences can (literally) be brain-changing  - and any talk of hard-wiring is to misunderstand neural development. Until social factors are controlled for, it is impossible to say any differences are solely due to gender. Our brains reflect the society we live in” – quite scary really when you watch kids adverts for toys.
What is also scary is that even at home males tend to be encouraged to be engineers, scientist and tradespeople, where girls are not. Heather finished off by encouraging us, the audience to do more – complain about gender stereotyping in adverts and shops, don’t be afraid to be a role model and educate others about the misconceptions about science. We left feeling enthused and determined to make a difference.

 

The day was a delightfully cheering account of some hugely inspiring female role models by some great characters, and a good excuse to go to the pub in London afterwards 

A Tale of Two Tokamaks - Post the Second

By James Edwards

See the story about the first tokamak in our tale – JET – here.

Culham Science Centre by Abingdon, Oxfordshire was an unusual place, even in the year one thousand nine hundred and ninety nine. It was very blocky, very industrial and mostly concrete. Unusual, in the sense that the 50s & 80s architecture of the buildings was starting to house the beginnings of the most recent developments of the high-tech types of power generation: spherical tokamak fusion.

Large changes were afoot, with the approach of the turn of the millennium not only bringing the not-quite-so-apocalyptic-as-the-media-made-out Millennium Bug, but also a new, larger type of spherical tokamak (ST, for short) than had ever been built before (funnily enough, named for its approximate shape).

The UK has its own fusion research and development programme, entirely independent of the Joint European Torus (JET). Over the years, dozens of experimental machines had been built at Culham to test out an array of different fusion concepts.

In 1997, construction had begun of the Mega-Ampere Spherical Tokamak (or MAST, for fans of the less wordy version, like myself). Its mission: to investigate how larger spherical tokamaks worked and affected the conditions for fusion.

MAST was built as a follow-on to the first purpose-built full size spherical tokamak called START (also at Culham). Although mostly assembled from spare parts, START had shown very promising results, so the UK government agreed to provide funding for the construction of MAST.

“What’s the difference?” you might (hopefully) be asking (and even if you’re not, I’m going to explain anyway). The concept of a spherical tokamak was introduced by Martin Peng at Oak Ridge National Laboratory in 1984, who suggested that the coils could be wired up in such a way as to reduce what is known as the aspect ratio of the tokamak, making it easier to get plasma cross sections that look like the capital letter “D”. (It had recently been found that plasma in this shape often had a better performance than other shapes that had been used before.)

In practice, the difference in shape means that STs can be just as good at confining the plasma as toroidal machines but with approximately ten times less magnetic field required and hence, more efficient. One downside of this is that in an ST, several magnets are typically (though not always) placed inside the machine, rather than outside (which is the usual design in a toroidal tokamak), so different aspects of the design, such as placement of magnetic coils and other components, need to be considered carefully.

Due to the research into STs and how they work still being at quite an early stage, it’s very unlikely they will be used for the first generation of fusion power plants, which will be more like JET and ITER in structure. They may have potential uses elsewhere though before that. For example, they could potentially be used as component test facilities to develop the various systems that will be required to operate a fusion power plant. Or more speculatively, it has been suggested that STs could reduce the amount of waste produced by current nuclear fission power plants through a process called nuclear transmutation.




MAST: the glow near the central column is where the fuel gets in to the vessel. You can see some of the coils winding their way around the back of the machine, seemingly segmented.

Anyway, back to MAST... operations started in 2000 and since then it has been investigating many various plasma conditions in STs as well as testing different diagnostic (experimental) systems that have been built and fitted to the machine over the years.

In particular, MAST has made advances in imaging diagnostics and techniques. Some of the more recent work that’s been done on MAST includes imaging different high speed plasma events, such as Edge Localised Modes (ELM) – a sudden release of pressure at the edge of the plasma (similar, but not the same as, a solar flare) – and getting pictures of the filament structures in the plasma during a disruption (an event that happens when control of the plasma confinement is suddenly lost).



Edge Localised Modes in MAST. You might notice they look similar to these coronal loops in the Sun’s atmosphere taken by NASA’s TRACE spacecraft. The similarity shows the magnetic field’s power for each of the two different plasmas.

ELMs are something that can be helpful to tokamaks in some situations and an annoyance in others, so other recent work has focused on analysing different techniques for controlling ELMs in MAST. This is helping to improve the plasma physics models required for future power stations, where ideally plasma events like this will be both reasonably predictable and controllable to keep the tokamak putting power on the grid steadily.

MAST continued running pulses up until October 2013, when it went into a period known as a shutdown. This one is special though, because unlike previous shutdowns, this time the machine is essentially being rebuilt to become MAST-Upgrade. One of the brand new systems being added is the Super-X divertor. (Quick note: the divertor in a tokamak was initially just meant to be used as an exhaust for the helium produced during fusion, but it turns out that with particular magnetic field shapes, it can also produce more efficient fusion plasmas by significantly improving confinement.) This particular type of divertor hasn’t been tried before, and is testing several engineering and plasma physics ideas.

Plasma in tokamaks is pretty hot stuff, so the divertor region gets a rather large amount of energy in the form of heat dumped on it during operations. One of these ideas is to test a new design in the shape of the divertor to allow the amount of power exhausted from the plasma to distribute over a larger area and provide a larger region for the heat to radiate away. This will dissipate the heat more effectively than the current divertor. You can get a rough idea of how it works in this short video.

The upgrade also allows us to improve the plasma positioning and control systems in place on MAST. This improvement in control means that the distance from the edge of the plasma to the nearest components will be about a centimetre or so (rather close, for something that is several thousand Celsius hot!).


The MAST upgrade is effectively a rebuild of the machine. The spherical part goes inside this container. All the circular sections are ports for diagnostic systems to be fitted to.

The MAST Upgrade project is expected to complete in late 2016 and we should see results from this large effort shortly after this. The results will be used when designing future STs as well as when making technology decisions during the design of a demonstration fusion power plant (particularly considering the new divertor design).

I’m sure you’ll be seeing more about the MAST upgrade project in the future on Tokamak Tales!

PS: Simultaneous thanks and apologies to Charles Dickens for inspiration.

Can Nuclear Fusion save the world?

by Ailsa Sparkes
 

When some of the graduates went to the KIT summer school on Fusion technologies last year (see blog post here), David Ward from CCFE gave a talk entitled ‘Future Energy and the Role for Fusion’. As well as leading CCFE’s Power Plant Technology Unit, David works at the Oxford Institute for Energy Studies, so is well placed to give an overview of fusion’s place in the energy market of the future. It was so well packed with interesting facts and figures that I thought I would convert his talk into a blog (with his permission!)
 

Future outlook
 

Most people are aware of the dire consequences facing the world at the moment due to global warming.  We’re beginning to see more and more examples of extreme weather globally and this has been partly attributed to all of the carbon dioxide that developed countries have emitted since the industrial revolution. Unfortunately the areas that usually get hit the hardest by this extreme weather are developing countries: nations that have contributed the least to these effects.

The graph below (Fig 1) shows the HDI (Human Development Index – a measure of GNP, health, education, etc.) for all OECD (developed) and non-OECD (developing) countries.  For all developing countries to reach the same HDI as the UK for example (~0.9), the world’s energy use would need to double, not accounting for any population increase. 

Figure 1



Figure 2 shows a graph of the energy consumption in Germany, China and India from 1965 until 2010. It shows that in just the final two years the growth in Chinese energy consumption has equalled the total energy consumption by Germany since 1965. Developing countries are becoming a match for energy consumption from developed countries. We must reduce emissions if we are to minimise climate change, yet we are faced with a massive increase in demand for energy. Decoupling this paradox will require dramatic changes in energy systems.
 

How can fusion help?

 

Renewable energy is making progress, and is steadily forming a larger proportion of energy production. In 2013 renewable energy contributed 15% to UK electricity compared to 11% the year before. Renewables have an extremely important part to play in our future, but many of them rely on certain weather conditions (solar, wind) and at the moment we do not have a viable energy storage solution (although progress is being made). Nuclear fission provides a reliable baseline energy supply with low carbon emissions, and fusion has the potential to do the same in the future, with even more advantages.

 

One of the fuels used in fusion is deuterium, which occurs naturally in water. A single litre of water contains 0.033g of deuterium, possessing energy equivalent to 10GJ or 280 litres of oil. There is enough deuterium around to provide energy for billions of years. The other fuel is tritium, which can be produced from lithium. The amount of lithium in one laptop battery would be enough for one person’s lifetime of electricity needs (240,000kWh). There are land based lithium reserves for at least thousands of years (from known supplies) to millions of years (from expected but unconfirmed reserves). The bottom line is that fuel reserves for nuclear fusion are enormous and not an issue.

 

Nuclear fusion is inherently safe – there is no chance of a ‘run-away’ reaction. Tritium is radioactive but has a short half-life of 12.5 years, so it decays quite quickly (long-lived fission products have a half-life of up to 200,000 years). It’s useful to put the amount of radioactivity we experience in our day-to-day lives in perspective. Figure 3 shows the amount of radiological exposure arising from activities which give us energy. The two highest doses are from food, and from improved double glazing – both of which go off the scale of the graph. Food is naturally radioactive, and double glazing increases our dose by introducing more radon into our homes. This graph is just to give context, and not compare means of energy consumption. None of these sources give us a damaging amount of radiation.

Figure 4 shows a 2007 prediction of the lifetime of various energy sources, assuming current demand. There is data for oil, gas, coal, uranium (for fission), breeder (for advanced fission) and lithium (for fusion). For each there is a ‘lower resource’ - what we know we have, an upper resource - what we think we may have, and ‘new’ resources - speculative considerations. These data are rather out of date, and do not include shale gas reserves but give a good overall idea of the future we face. Oil, gas and coal are probably going to run out very soon, and even if they don’t we need to curb their usage. Even uranium for fission doesn’t give us a very long outlook. Advanced fission reactors and fusion would see us far into the future, with very low carbon emissions. 

Fusion’s bad press

There are lots of good things about nuclear fusion, and when we get it working, it has the potential to largely solve our energy problems. However, it has had rather a bad press in the last few years. The typical joke is that ‘fusion is always 30 years away’. What rarely gets reported is how much progress we have made in fusion, the technologies that have advanced due to fusion research, and how much we now understand relative to even 10 years ago. What often gets reported is that we have an international project called ITER, which will be the largest fusion reactor so far, and for which construction has overrun and has gone over budget. This is true, and the management of the project is now being reorganised to address these problems. The estimated total cost of ITER is 15 billion euros, which is a huge amount of money, but it’s interesting to compare this to other costs. The total cost of ITER amounts to the same world expenditure on two days’ worth of oil. Figure 5 shows the estimated amount spent globally on different energy sources. Overall, the amount spent on public sector research and development is a negligible fraction, and of that, fusion is a tiny fraction.

 

 

The Future

 

If we consider hypothetical future energy scenarios, in a world where there is no constraint on carbon emissions, we are totally dependent on coal and fission. In a low carbon future – fission and renewables provide the growth needed for about 50 years. After that, fission needs to be replaced by ‘advanced nuclear’ which includes fast breeders and fusion. Alternatively, fission may be constrained due to public concerns and fusion may be required earlier. However, if fission is rejected by the public, it is uncertain whether fusion will be more or less likely to contribute meaningfully.

World energy consumption is likely to more than double, even with a cap on it. There is therefore an enormous potential market for low pollution, low carbon energy sources. Fusion has huge benefits in terms of resources, environmental impact, safety and waste materials. Those doing research into fusion power must focus on demonstrating its potential as a power source, ensuring the benefits are optimised and keeping costs reasonable. If we are to achieve the transformation required in energy markets, the world needs to invest much more in fusion and in energy research and development as a whole.

For more information please see David Ward’s publication

http://www.sciencedirect.com/science/article/pii/S092037960700083X

Inspiring the ITER generation - CCFE's Fusion Workshop

by Sarah Medley

It’s a really exciting time for fusion research right now – we’re building the next-generation tokamak ITER and we’re working towards a demonstration power station (known as DEMO), to put fusion electricity on the grid before 2050. However, the dream of fusion as the ultimate energy source will never become reality without one essential ingredient: people! We need people to continue the research, to operate ITER and design DEMO! So it is essential that the fusion community considers how to inspire this next generation of fusion scientists and engineers - often referred to as “the ITER generation”.

Fortunately, CCFE already has a strong outreach programme dedicated to this goal. We give tours of our JET and MAST fusion experiments to A-level and university students, and we take the Sun Dome science roadshow into primary schools. However, the graduates realised that there was a ‘gap in the market’ when it comes to secondary school students, so we decided to develop something specifically aimed at inspiring GCSE-age students to pursue Science, Technology, Engineering and Maths (a.k.a. STEM) subjects to A-level and beyond!

And behold, the CCFE Fusion Workshop was born. Developed entirely by CCFE graduates, the Fusion Workshop is an interactive activity session that uses hands-on science and engineering demonstrations to bring the real-world applications of STEM subjects to life in the context of fusion research. What exactly does that mean, you ask? Well basically we assemble a crack team of graduates, pile them into a van with a load of demonstration kits and send them off to a local school to invade a GCSE physics lesson.
 

The Fusion Workshop team. From left to right: Jim (materials scientist), Alastair (physicist), Greg (mechanical engineer), Kim (control engineer), Sarah and Alex (physicists).

 School lessons only last for an hour, so the Fusion Workshop is designed to be a snappy and exciting insight into the world of fusion research and why it’s so awesome, all delivered in less than 60 minutes. We kick off the session with a short intro to fusion and CCFE, before diving into the best bit – the demos! This is where the students get to have a great time playing with lasers, magnets, expanding marshmallows, and not forgetting the robotic arm chocolate relay race! Of course, it’s not just about having fun, as the graduates are on hand to provide easily understandable explanations of how each demo relates to a particular element of fusion research, whether it’s plasma diagnostics or vacuum technology. So the demos all aim to show how the science taught at school is actually applied in the real world of fusion research! We wrap up the workshop with a quick chat about how to become a scientist or engineer - and why it’s such an exciting career choice! - then we pack up the van and drive off into the sunset (or back to CCFE), happy in the knowledge that the students all had fun and are hopefully now considering STEM career routes as a result of the session.

Of course, this is how we see it, but what do the students think? Well, the feedback speaks for itself – after trialling the workshop with a local year 10 class, we received comments such as “I loved it and it just made me want to go to university and be an engineer” and “I am hoping to become a physicist when I'm older and this has really enthused me”. One member of the class has even applied for work experience at CCFE, as a direct result of our workshop.

So you put a marshmallow inside a vacuum chamber, switch on the pump, and then….? Greg and Sarah show these two year 10 students what happens and why.

 

Future remote handling engineers?

Unsurprisingly, adults enjoy the workshop session just as much as school students. We witnessed this first hand last month at a networking event that we co-hosted with Science Oxford, where 25 teachers and STEM Ambassadors from across the country came to CCFE to experience the workshop for themselves! This was an excellent opportunity to give us invaluable feedback, which we can now use to refine the workshop and develop it further.
The plan is to continue to work closely with teachers and schools to make sure that the students really are getting the most out of the workshop, and then it can be officially rolled out later this year!


Jim explains to teachers how the GCSE physics concepts of reflection and refraction are applied to JET’s essential laser diagnostics.

Alex explains to teachers how we use ferrofluids in the workshop to illustrate magnetism to students. Magnets are the most essential part of any tokamak!

So, what started out as an enthusiastic group of graduates with a vision is now a very real project with a lot of momentum, and we’re super excited about it. The workshop also has great potential to incorporate other demos in future, for example other graduate projects such as the table-top plasma device or RIFT, so watch this space! Whatever happens, we hope that the CCFE Fusion Workshop will continue to inspire young scientists and engineers for years to come!

Spectroscopy – more than meets the eye

by Jamie Zacks

 

There must be hundreds, if not thousands, of diagnostic techniques used by scientists around the world, but one that I quite admire is spectroscopy. 

Now there are some scientists who would automatically assume I’m talking about mass spectroscopy, which is a valuable tool for measuring the mass of particles in a system, so you can figure out which atoms or molecules are present.   I, however, am talking about the splitting of light into its constituent wavelengths.

There are stories you hear of tailors who can accurately guess your size from one brief glance at you, and other tradesmen who take one quick look, and can see the problem.  For me, the beauty of spectroscopy is that is it essentially just taking a look, all be it with some slightly more fine-tuned instrumentation than the human eye.  Spectroscopy is, on the whole, passive (I’ll come to some examples considered non-passive later):  Light is emitted by a system, and we just put a device in there to collect some of it.  It’s what we can do with this information which I think is rather impressive.

Figure 1 - Spectroscopy principles

How do we use Spectroscopy at JET?

On JET we have spectrometers covering a large range of the electromagnetic spectrum, from infra-red (~1000 nm) through to the visible (400-700nm) down to the UV (300nm), VUV (Vacuum Ultra Violet ~10-200nm)), XUV (<10nm), XRay(<1nm).  Due to the high temperatures inside the JET plasma, most of the visible emission comes from the edge region.  As you move further into the centre of the plasma, it gets hotter, and the wavelengths seen are usually much shorter, until there’s very little spectral emission we can detect.  Spectrometers can actually take a number of guises.  Some have a grating and will separate light over a specific wavelength range, others may just be a narrow-band filter (a few nm) and a detector.

The first and most obvious use for spectroscopy is to identify the atoms and molecules emitting the light.  The differing electronic structures of particles emit light with a unique set of wavelengths, acting as a signature.  In tokamaks like JET or MAST, we know that the plasma is mostly made of deuterium which gives a pinkish colour due to the main spectral lines at 656nm (in the red), 486 (blue) and 434 (violet). However there are a number of other elements that can be seen in the plasma, and spectroscopy allows us to look for the weaker sources of light.

Figure 2 - Hydrogen Balmer spectrum

In some JET plasma pulses, it has been possible to see carbon, beryllium, tungsten, copper, iron, helium, oxygen, nitrogen and neon.   A lot of these appeared due to their presence in the vessel components, and are often monitored for each pulse.  If the JET plasma is experiencing problems, one possibility is that impurities are causing it, so being able to identify the impurity through spectroscopy is very useful.  During a recent failure of a vacuum isolation valve between JET and one of the neutral beam injection (NBI) beamlines, impurities were seen when the NBI plasma heating system was firing.  This was quickly identified as being copper thanks to one of the spectrometers, and although it didn’t identify the source completely, it showed operators the level of the problem. When copper is being put into the plasma by NBI, it means something is getting damaged, and this could cause a water leak from the extensive cooling system on JET.

Figure 3 - Spectra for various elements

Is it really so simple?
 

Sometimes the impurities present in the plasma aren’t so easy to identify.  If an element has been seen in the plasma previously and has a simple reason for being there, one or two of the stronger lines it emits can be monitored.  If, however there is an impurity problem but none of the usual suspects is showing high levels, things can get a bit more complicated.  When monitoring just a couple of lines, you don’t need to look at the whole wavelength range captured by the spectrometer and recorded on a CCD (Charge coupled device) camera or PDA (Photo-diode array).  You just have a program to analyse the sections of the data that you know the line falls on.   When you don’t know what the problem is, you have to start analysing the whole spectrum by eye, looking for unusual lines that aren’t accounted for by the normally seen impurities.  If you find a line, there is still a lot to do to identify the source of it.  You need to find which materials emit lines at that particular wavelength, and then look for the other lines they would emit, to confirm the identification.  This can be quite a tedious task when you don’t know what you’re looking for, and all the different elements, with all their different ionisation stages can produce a lot of lines throughout the electromagnetic spectrum.

Not quite 10 years ago on JET, there was an impurity problem, again when NBI was running.  This time, however, the copper levels remained unchanged, leaving a number of people scratching their heads.  Eventually, using spectroscopy, the impurity was identified as titanium, which has no business being inside JET!  It was actually found to be from titanium oxide, which is used as a whitening agent in masking tape, a small piece of which had been left on a beamline component, and was slowly being eroded by the neutral beam, sending particles into the JET plasma.

Sometimes trace amounts of impurities are injected into JET on purpose, using either a gas puff, or laser ablation for metallic elements.  Using spectrometers to monitor the locations of these elements helps our understanding of how materials move about in the plasma.

Now, I’ve gone on about the matter of identification of elements a bit longer than I intended, but just wanted to highlight that it’s not easy if you don’t know exactly what you’re looking for.  Now I’m going to talk about the really cool (I only say that slightly ironically) stuff we can get from spectroscopy, in particular on tokamaks.

What else can spectroscopy tell us about plasmas?

The Doppler effect is a pretty well-known effect that if something emitting light is moving fast enough, the wavelength seen will shift red if it’s moving away, blue if it’s moving closer.  This is a pretty key idea in astrophysics and cosmology.  In plasma physics, we have a hot gas emitting light.  This gas will be moving in all directions, so what you see is a broadening of the spectral line, with the width of the line corresponding to the energy and temperature of the emitting material in the plasma.  If your resolution is good enough, and the plasma hot enough, this width can easily be measured, and voila, you have some useful plasma parameters.

Each element has numerous spectral lines associated with it, and the relative intensities of these lines can tell us quite a lot.  If, with computer power, we can accurately model the mechanisms that excite the electrons in an emitting atom, we can often calculate plasma electron temperatures and densities, ionisation and recombination rates, and densities of other species that interact with the emitting species.  The types of mechanism considered will be thermal excitation, collisions with plasma electrons, excitation by light, or collisions with other elements.  Some parameters such as the electron temperature and density can be measured by alternate methods, but most of these will be invasive to some degree, which means we may affect the behaviour of whatever we are measuring.  As I said earlier, the beauty of spectroscopy is that it can be passive. 



Figure 4: Spectrometer on the Small Negative Ion Facility (SNIF) at CCFE. Looks at molecular and atomic hydrogen spectrum.

If we look at the spectrum emitted by a molecule, there are a lot of small lines due to the vibration and rotation of the molecule, and again, line ratios can help find the energy in these.
 

Figure 5: Example of hydrogen molecular spectrum on SNIF

Similar techniques, along with some very impressive telescopic instrumentation, which just require us to look with our eyes, have given us so much information about what is taking place out in the solar system and the universe beyond, as well as inside a tokamak, such as understanding the power produced by the sun – vital if we want to recreate it!

Figure 6: Example of how Thompson Scattering spectra are used

 

Not so passive spectroscopy…

Just a quick note on some of the non-passive techniques that use spectroscopy:  In tokamaks these can be grouped into Thompson Scattering, and Charge Exchange Spectroscopy.  The former fires a laser through the plasma, and as the light is scattered by the plasma electrons, it is Doppler shifted.  Analysis of the shifts was one of the first techniques used on a tokamak to obtain the electron temperature.  The intensity of light scattered can also give the density.  Charge Exchange spectroscopy, and some derivatives such as Motional Stark Effect spectroscopy, make use of the interaction of the neutral beam heating particles with the plasma particles.  The light emitted can be analysed to give velocity and rotation information for the plasma.

So, in conclusion, I just want to say that it’s impressive that we can learn so much by essentially just looking. 

Thanks for reading.