THE BOOTSTRAP CURRENT IN A TOKAMAK WITH ELECTRON-CYCLOTRON HEATING

The bootstrap current in a non-Maxwellian tokamak plasma with electron cyclotron heating is calculated. The calculation is exact in the limi t of highly charged ions, where pitch-angle scattering dominates over quasilinear diffusion, and shows that the current is entirely determin ed by the pressure of the trapped electrons. If the ion charge is fini te, the current is shown to consist of two terms: one driven by collis ions, and one driven by the heating and losses. The former is calculat ed approximately by using a model collision operator, and is found to be determined by the distribution of trapped electrons alone; the latt er is discussed qualitatively.