Evidence of stabilization in the Z-pinch

Area of Science:

• Plasma physics
• Magnetohydrodynamics
• Fusion energy research

Background:

• Z-pinch devices are prone to magnetohydrodynamic instabilities.
• Theoretical models suggest axial flow shear can stabilize Z-pinches.
• Previous experiments lacked sufficient axial flow to test stabilization theories.

Purpose of the Study:

• To experimentally verify if sheared axial flow can stabilize Z-pinch plasma.
• To measure magnetic fluctuations and velocity profiles in a flowing Z-pinch.
• To compare experimental results with theoretical predictions for stability.

Main Methods:

• Designed and operated a Z-pinch experiment to generate significant axial plasma flow.
• Utilized magnetic probes to measure magnetic fluctuations.
• Employed diagnostic techniques to determine plasma velocity profiles.
• Analyzed data to correlate velocity shear with plasma stability and magnetic fluctuations.

Main Results:

• Observed a stable plasma period exceeding 700 times the expected instability growth time for a static Z-pinch.
• Experimentally confirmed that axial velocity shear surpassed the theoretical stabilization threshold during the stable phase.
• Found axial velocity shear dropped to near zero as magnetic fluctuations increased, indicating instability onset.

Conclusions:

• Experimental results strongly support the theory that sufficient axial flow shear stabilizes Z-pinch plasmas.
• The study demonstrates a viable method for controlling Z-pinch instabilities through flow dynamics.
• Findings have implications for designing future fusion energy devices utilizing Z-pinch configurations.