Experimental Evidence of High-Beta Plasma Confinement in an Axially Symmetric Gas Dynamic Trap

Abstract

In the axially symmetric magnetic mirror device gas dynamic trap (GDT), on-axis transverse beta (ratio of the transverse plasma pressure to magnetic field pressure) exceeding 0.4 in the fast ion turning points has been first achieved. The plasma has been heated by injection of neutral beams, which at the same time produced anisotropic fast ions. Neither enhanced losses of the plasma nor anomalies in the fast ion scattering and slowing down were observed. This observation confirms predicted magnetohydrodynamic stability of plasma in the axially symmetric mirror devices with average min-B, like the GDT is. The measured beta value is rather close to that expected in different versions of the GDT based 14 MeV neutron source for fusion materials testing.

Future Perspectives and Status of Magnetic Mirror Studies in Novosibirsk

“…Basically, it is a result of a pulse character of the experiments and transient regimes of plasma accumulation in anchor cell of the device. In the experiments with accumulation of the fast ions, the β value in their turning points near the end magnetic mirrors reaches ∼ 0.6 close to theoretical stability limit against ballooning [18]. The cross-field transport suppression by induced plasma rotation was observed.…”

Wall stabilization of the rigid ballooning $m=1$ mode in a long-thin mirror trap

“…Probably oblivion for many years of Lodestro's work is due to the early termination of the TMX (Tandem Mirror eXperiment) and MFTF-B (Mirror Fusion Test Facility B) projects in the USA in the same 1986 [3]. However, achievement of a high electron temperature and high beta in the Gas-Dynamic Trap (GDT) at the Budker Institute of Nuclear Physics in Novosibirsk [4][5][6][7][8][9][10][11][12], emergence of new ideas [13] and new projects [14,15] makes us rethink old results.…”

Optical tomography diagnostic for study of neutral plasma component in the gas dynamic trap

“…Study of axial transport [3] is one of ongoing physical objectives of the GDT research program. In high-beta regimes [4] with electron cyclotron resonance heating (ECRH) [5], extra efforts must be spent to stabilize the plasma against magneto-hydrodynamic (MHD) perturbations. This line of experimental and theoretical activities has led to establishing of the so called vortex confinement [6] method of MHD modes suppression which is now a standard attribute of experimental scenarios in GDT.…”