Helium ash alpha-particles at 100keV in magnetically confined fusion plasmas may have the same Larmor radius, as well as cyclotron frequency, as the energetic beam-injected deuterons that heat the plasma. While the velocity-space distribution of the helium ash is monotonically decreasing, that of the energetic deuterons is a delta-function in the edge plasma. Here we identify, by means of first principles particle-in-cell computations, a new physical process by which Larmor radius matching enables collective gyroresonant energy transfer between these two co-located minority energetic ion populations, embedded in majority thermal plasma. This newly identied phenomenon rests on similar underlying physics to widely observed ion cyclotron emission from suprathermal minority ion populations.
A new mechanism for collective energy transfer from neutral beam-injected ions to fusion-born alpha-particles on cyclotron timescales in a plasmaA new mechanism for collective energy transfer from neutral beam-injected ions to fusion-born alpha-particles on cyclotron timescales in a plasma https://scientific-publications.ukaea.uk/wp-content/themes/blade/images/empty/thumbnail.jpg 150 150 UKAEA Opendata https://secure.gravatar.com/avatar/679db0b751d3e5fa797cd4b46afe6f58?s=96&d=mm&r=g
The published version of this paper is currently under embargo and will be available on 10/03/2024