Derek Robinson (physicist) facts for kids

Derek Charles Robinson (born May 27, 1941 – died December 2, 2002) was a brilliant physicist. He spent most of his career working on the UK's program to create fusion power. This is a way to make energy like the sun does.

Robinson studied something called "turbulence" in a machine called ZETA. He helped create an idea called the reversed field pinch, which scientists still study today. He is most famous for a key measurement he made in 1969 on a machine called T-3 in the USSR (now Russia). This measurement proved that a type of machine called a tokamak was the best way to try and achieve magnetic fusion energy.

He also played a big part in developing a special kind of tokamak called the spherical tokamak. This led to building machines like START and MAST. From 1979, Robinson was in charge of parts of the UK's fusion program. He then led the whole program from 1996 until he passed away in 2002.

Early Life and Education

Derek Robinson was born in Douglas, on the Isle of Man. Because his father was in the Royal Air Force, Derek moved around a lot. He went to many different primary schools.

When he was in secondary school, he was excellent at science and math. He decided he wanted to become a physicist. He also loved church and organ music, which started when he sang in his local church choir.

He went to the Victoria University of Manchester and was the top physics student in his year. His professor, Brian Flowers, introduced him to scientists at the Atomic Energy Research Establishment, also known as "Harwell." Derek then worked on his PhD in Physics with Sam Edwards.

Solving ZETA's Mystery

Harwell had a very big and powerful fusion machine called ZETA (fusion reactor). When ZETA first started in 1957, it released many neutrons. Neutrons are a sign of nuclear fusion reactions. Measurements suggested the machine reached 5 million degrees, which seemed hot enough for some fusion.

In January 1958, when ZETA's first results were shared, a scientist named John Cockcroft said he was 90% sure the neutrons came from fusion. But this turned out to be wrong. The reactor was actually much cooler, too cool for fusion. The claims had to be taken back in May, which was a big embarrassment.

Scientists later understood that the neutrons came from small, unstable events inside the plasma (the super-hot gas). Earlier problems with ZETA had been fixed, but new ones appeared. These new problems were caused by turbulence within the plasma. Derek Robinson was given the job of understanding this turbulence better.

He did many experiments to study it. His work helped scientists understand the problem better. This led to important work by John Bryan Taylor on a new theory about electric currents in magnetic fields. This was a big step forward in plasma physics. It also introduced the idea of the reversed field pinch, which is still studied today.

As these problems became clearer, the ZETA team focused on making better tools to study the plasma. Instead of just measuring light from the plasma, they could directly measure the speed of electrons using a method called Thomson scattering. This needed a very bright and pure light source. When the laser was invented in the 1960s, it provided this light. By 1964, the Harwell team became experts in using lasers for these measurements.

The T-3 Breakthrough in Russia

Since the mid-1950s, scientists in the Soviet Union (Russia) had been quietly developing a machine called the tokamak. A tokamak is similar to ZETA. It has a ring of magnets around a donut-shaped tube, and a large transformer creates a current in the plasma. The magnetic fields mix to create a spiral field around the plasma.

The main difference was how strong the magnetic fields were. ZETA's field came mostly from the transformer current. Tokamaks used stronger ring magnets to balance the fields more evenly. This small change made a huge difference in how the plasma behaved.

By the mid-1960s, experiments showed that the tokamak was much better than older designs. However, the Soviets waited to announce their results. They wanted to be absolutely sure, perhaps to avoid a problem like the ZETA situation. Their work continued into 1967 and 1968.

At a conference in August 1968, the Soviets announced amazing results from their latest T-3 reactor. The plasma reached 10 million degrees, and the hot plasma stayed contained for over 10 milliseconds. There were clear signs of fusion. The fusion science community was shocked. These machines were much better than any other device, even bigger ones. Many people wondered if the results were real.

Lev Artsimovitch, a Soviet scientist, invited "Bas" Pease to bring the ZETA team to the T-3 machine in Moscow. This was a unique chance, especially during the Cold War, a time of tension between the West and the Soviet Union. The British government was worried about their scientists sharing secrets. So, UK scientists with important knowledge could only travel to the USSR if a "reliable person" went with them. Derek Robinson solved this by marrying Marion Quarmby in 1968. He also took a quick course in Russian!

The "Culham Five" team, led by Nicol Peacock, arrived in 1969. Their first experiments were difficult. Derek Robinson led the effort to make their ruby laser 100 times more powerful. With the stronger laser, the signal was clear. Their measurements confirmed the Soviet results, showing temperatures around 20 million degrees. Their paper, published in a science magazine called Nature in November 1969, changed fusion research forever. Almost every other design concept was dropped, and scientists focused on tokamaks.

Evgeny Velikhov, president of the Kurchatov Institute, later said: "Derek Robinson was highly respected in Russia ever since his visit in 1968. His measurements of the electron temperature in the T-3 plasma started active research on tokamaks all over the world. Derek was known for his brilliant science and bright personality. He was an extremely friendly, charming, clever, and intelligent person, who will be remembered by all who met him."

New Tokamaks and STs

When Derek Robinson returned to the UK in 1970, he moved to the UKAEA laboratory in Culham. This lab was bringing together all the UK's fusion efforts. He led the team to build the UK's own tokamak, called COMPASS.

Later experiments showed that non-circular shapes for the plasma might work better. So, Robinson led the effort to change COMPASS into COMPASS-D, which had a tear-drop shaped plasma area. COMPASS-D proved this idea worked. Today, a D-shaped plasma is a feature of all modern tokamak designs.

Derek was always looking for new solutions. So, he was very open to an idea from Martin Peng of the Oak Ridge National Laboratory (ORNL) in the US. Peng was trying to get interest in the spherical tokamak (STs) concept. STs were basically smaller tokamaks. But they had features that suggested they could perform much better than regular designs. ORNL had designed a machine called "STX" to test this, but they couldn't get money to build it.

Robinson managed to get £10 million. This was enough to build the main vacuum chamber and most of the support equipment. Other parts, like a neutral beam injector, were "loaned" from ORNL to stay within budget. The machine, called START, started working in 1991. It immediately produced results that were as good as, or even better than, almost every other machine in the world. And those other machines cost much more! START's success led to similar machines being built worldwide, including Culham's own MAST.

Leading the UK Fusion Program

In 1990, Derek Robinson was chosen to represent the UK on the Joint European Torus (JET) project. Culham was chosen as the place to build JET. Six years later, he became a member of JET's board.

He was elected a fellow of the Royal Society in 1994. In 1996, he became the director of fusion at UKAEA. Robinson was also a fellow of the Institute of Physics. He was actively involved in designing the International Thermonuclear Experimental Reactor (ITER), a huge international fusion project.

Derek Robinson passed away from cancer on December 2, 2002, at the Sobell House Hospice in Oxford. He was survived by his wife Marion and daughter Nicola.