Experimental observation of the hot-electron equilibrium in a minimum-<i>B</i>mirror plasma

Abstract

Measurements of the hot-electron (T=450 keV, n=2\ifmmode\times\else\texttimes\fi{}${10}^{11}$ ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}3}$) equilibrium in the Constance B minimum-B magnetic mirror show that the pressure profile is peaked off the axis and is shaped like the seam on a baseball. This curve is the drift surface of the deeply trapped electrons and the location of the strongest microwave heating. The configuration is stable and decays quiescently on the hot-electron collisional time scale (1--2 s) after the microwave power is turned off. According to 1D pressure-weighted F dl/B analysis this plasma configuration is expected to be unstable.