Can radio-frequency waves help to make the plasma rotate?

Two scientists from the Massachusetts Institute of Technology, Yijun Lin and John Rice, claim to have demonstrated an efficient method for using radio-frequency waves to make the plasma rotate inside a tokamak. Rotation would not only help to prevent it from losing heat to the walls but also prevent internal turbulence that could reduce the efficiency of fusion reactions. The results of the experiments are detailed in the 5 December issue of the journal Physical Review Letters.

But just how this method exactly works is yet unclear—so far there seems to be no satisfying theoretical foundation for why it works as it does. "This is a very interesting experimental observation," says Wayne Houlberg, Head of the Integrated Modelling Group within the ITER Organization. "It could be relevant to ITER's interest in controlling plasma rotation, which we know has a strong influence on plasma transport and stability. However, the result is very new and complex—its applicability to the deuterium-tritium (D-T) plasma conditions we expect in ITER will take time to evaluate."