Laboratory Resolved Structure of Supercritical Perpendicular Shocks

Area of Science:

• Plasma Physics
• Magnetohydrodynamics
• Laboratory Astrophysics

Background:

• Supermagnetosonic perpendicular flows are key phenomena in astrophysical and laboratory plasmas.
• Understanding the plasma-piston coupling is crucial for controlling plasma behavior.

Purpose of the Study:

• To resolve the full structure of plasma-piston coupling in a laboratory experiment for the first time.
• To investigate the role of ambipolar potentials and Hall currents in magnetically driven flows.

Main Methods:

• Utilized a large radius theta-pinch experiment.
• Employed fine spatial resolution and macroscopic coverage for detailed observation.

Main Results:

• Observed a moving ambipolar potential reflecting unmagnetized ions at twice the piston speed.
• Identified magnetized electrons balancing radial potential via Hall currents.
• Detected signature quadrupolar magnetic fields generated by electron dynamics.
• Found adiabatic electron heating in the reflected ion foot.

Conclusions:

• Provides the first complete laboratory resolution of plasma-piston coupling in supermagnetosonic flows.
• Elucidates the mechanisms of ion reflection and magnetic field generation.
• Offers insights into electron dynamics and heating in these complex plasma structures.