Achieving a long-lived high-beta plasma state by energetic beam injection

Area of Science:

• Plasma physics
• Fusion energy research
• Magnetic confinement fusion

Background:

• Achieving high-beta plasma is crucial for economic magnetic fusion reactors.
• The field-reversed configuration (FRC) is a leading approach for magnetic fusion.
• Disruptive magneto-hydrodynamic (MHD) instabilities, like the tilt mode, hinder FRC development.

Purpose of the Study:

• To investigate the kinetic stabilizing effect of fast ions on the disruptive tilt mode in FRCs.
• To demonstrate the combined efficacy of energetic beam injection and active plasma boundary control for stabilizing FRCs.
• To achieve a stable, ultra-high-beta plasma state with a long confinement time.

Main Methods:

• Energetic beam injection to introduce fast ions into the plasma.
• Active plasma boundary control techniques.
• Experimental demonstration of plasma stabilization.

Main Results:

• Demonstrated kinetic stabilization of the disruptive tilt mode by fast ions.
• Achieved a fully stable ultra-high-beta plasma state (approaching 100%).
• Observed a long plasma lifetime due to the combined stabilization techniques.

Conclusions:

• Fast ion kinetic effects are crucial for stabilizing disruptive MHD instabilities in FRCs.
• The synergistic combination of energetic beam injection and active plasma boundary control is a viable strategy for stable, high-beta fusion plasmas.
• This approach overcomes a major obstacle, paving the way for advanced FRC development towards economic fusion energy.