Achievement of a New High-Confinement, Collisionless FRC State in TCS-Upgrade

Reducing impurity radiation and overall recycling in the Translation, Confinement, and Sustainment Upgrade (TCSU) device enabled the plasma to enter into a new, collisionless regime with temperatures well over 200 eV, substantially exceeding the radiation barrier. This new field reversed configuration (FRC) state exhibits the following key features: (1) dramatic improvement in current drive efficiency with ζ (ratio of average electron rotation frequency to RMF frequency) approaching 100%; (2) up to 3-fold increase in global energy confinement time; and (3) significant reduction in transport rates, accompanied by a striking transition from a Bohm-like transport to a Lower Hybrid Drift (LHD)-like transport that scales better than gyro-Bohm and as such is very favorable for next step FRC development.