Magnetohydrodynamic Activity in High-β, Currentless Plasmas in Heliotron-E

Electron-cyclotron and neutral-beam heating have been used to produce currentless plasma with 〈β〉≈(1-2)% in the Heliotron-E device. For moderately peaked profiles, magnetohydrodynamic activity that peaks at the $t=1$ surface has been observed. The characteristics of the fluctuations are consistent with theoretical expectations for an $m=1$ pressure-driven instability. The magnetohydrodynamic activity is associated with particle and energy losses but has not yet been directly linked to global confinement.