Understanding Turbulent Ion Heating in the Oak Ridge Mirror Machine, "Burnout V"

Abstract

For several years, we have been empirically producing steady-state, mirror-confined hot-ion plasmas with $T_i\approx \mathrm{a}$ few keV and $n_i\approx \frac{{10}^{13}}{{\mathrm{cm}}^3}$. We describe here the ion-heating mechanism, which is an instability having a fine-grained azimuthal structure covering a broad band of frequencies around ${\omega }_{\mathrm{pi}}$, having a rapid growth rate on the order of ${\omega }_{\mathrm{pi}}$, and being driven by an intense radial dc electric field. It does not require that $T_e>T_i$.