Natural Hot Ion Modes in a Rotating Plasma

TL;DR

This paper explores how in a rotating plasma, certain conditions naturally lead to a hot-ion mode, where fuel ions are heated efficiently, depending on plasma profiles and alpha particle removal methods.

Contribution

It demonstrates that a hot-ion mode can emerge naturally in rotating plasmas under minimal assumptions about plasma profiles and alpha particle removal.

Findings

Hot-ion mode can arise naturally in rotating plasmas.

The dominant heating channel depends on plasma profiles.

Alpha particle removal influences the emergence of hot-ion modes.

Abstract

In steady state, the fuel cycle of a fusion plasma requires inward particle fluxes of fuel ions. These particle flows are also accompanied by heating. In the case of classical transport in a rotating cylindrical plasma, this heating can proceed through several distinct channels depending on the physical mechanisms involved. Some channels directly heat the fuel ions themselves, whereas others heat electrons. Which channel dominates depends, in general, on the details of the temperature, density, and rotation profiles of the plasma constituents. However, remarkably, under relatively few assumptions concerning these profiles, if the alpha particles, the byproducts of the fusion reaction, can be removed directly by other means, a hot-ion mode tends to emerge naturally.