Soft X-Ray Measurement on the Collisional Merging Process in a Field-Reversed Configuration

Abstract

To investigate excited shockwaves in a collisional-merging field-reversed configuration (FRC), soft X-ray (SXR) measurement was initiated on the FRC amplification via translation collisional merging (FAT-CM) instrument. Since the FRCs collide at a relative speed of 300-400 km/s on the FAT-CM, which is faster than the Alfvén velocity in the separatrix, shockwaves are assumed to be excited in the colliding FRCs. These excited shockwaves would play an important role in energy conversion during the collisional merging formation process of the FRC. The relation between the global behavior of the FRC in the collisional merging process and the time evolution of SXR signals are discussed herein.

Observation of self-organized FRC formation in a collisional-merging experiment

“…Therefore, the observed fusion reaction appears to be caused by the particles accelerated to the order of a few hundred keV in the excited shocks. Soft x-ray (SXR) radiation detected by a surface-barrier diode with 37.5 μm Be filter also shows a pulsed rise around t ∼ 40 μs and following thermalization as shown in figure 6(b) [21]. Gradual increase in the SXR intensity is consistent with the thermal equilibrium time of several tens of microseconds between ions and electrons of the FRC plasma.…”

Energy Flow in the Super Alfvénic/Sonic Collisional Merging Process of Field-Reversed Configurations

“…Therefore, a D-D reaction in thermal This observation suggests ion acceleration and its dependency on the relative velocity at the collision. In previous work, related ramp up of soft X-ray radiation, which indicates plasma heating, has also been observed after collisional merging [15]. Comprehensively considering these results, it is expected that shockwaves are excited via collision of plasmoids at super Alfvénic/sonic speed and that the excited shock causes energy regeneration of kinetic energy back into thermal plasma energy.…”