Quantifying fusion born ion populations in magnetically confined plasmas using ion cyclotron emission

TL;DR

This paper demonstrates through nonlinear kinetic simulations that ion cyclotron emission (ICE) intensity scales linearly with fusion alpha-particle concentration, confirming its potential as a diagnostic tool for fusion plasmas.

Contribution

It provides the first fully nonlinear simulation confirming the ICE scaling with alpha-particle concentration, resolving key questions about alpha confinement and stability.

Findings

ICE intensity scales linearly with alpha-particle concentration

Simulations confirm magnetoacoustic cyclotron instability as emission mechanism

Strengthens ICE's role as a diagnostic in future fusion devices

Abstract

Ion cyclotron emission (ICE) offers unique promise as a diagnostic of the fusion born alpha-particle population in magnetically confined plasmas. Pioneering observations from JET and TFTR found that ICE intensity $P_{ICE}$ scales approximately linearly with the measured neutron flux from fusion reactions, and with the inferred concentration, $n_\alpha/n_i$, of fusion-born alpha-particles confined within the plasma. We present fully nonlinear self-consistent kinetic simulations that reproduce this scaling for the first time. This resolves a longstanding question in the physics of fusion alpha-particle confinement and stability in MCF plasmas. It confirms the magnetoacoustic cyclotron instability (MCI) as the likely emission mechanism and greatly strengthens the basis for diagnostic exploitation of ICE in future burning plasmas.