Theory of the straight field line mirror and magnetic confinement
Author: Olov Ågren
Submitted: 2005-12-19 12:26:34
Co-authors: Vladimir Moiseenko, Natalia Savenko
Uppsala, Uppsala 75121
The straight field line mirror gives the optimal ellipticity of the flux tube for MHD stable mirror plasma. In this particular vacuum field, each gyro center bounces back and forth on a single flux line, with simple forms of the constants of motion. They are used to derive Vlasov equilibria, and the local omnigenuity (i.e. zero banana widths) is preserved to first order in the plasma beta. A scenario is presented to obtain a fusion reactor with a high energy gain by a modified thermal barrier. The end plugging involves separate ICRF heating on the minority D ions and majority T ions. RF heating instead of neutral beam injection may produce sloshing ions, which are known to strongly suppress microinstabilities. Detailed RF heating calculations for a 100 m long mirror fusion reactor model is presented.
A recent derivation of four stationary motional invariants in general adiabatic equilibria is presented. The four invariants include, apart from the energy and the magnetic moment, a radial drift invariant, which determines the density radial profile and the diamagnetic drift, and an additional parallel invariant that determines the plasma current along the magnetic field. Thus, there are in general more than three stationary invariants for the adiabatic motion of a gyrating particle. In the straight field line mirror, the motional invariants have a particularly simple form.
We are also prepared to give a poster presentation, in case the presentation would not be accepted for an oral presentation.