A new multi-line cusp magnetic field plasma device (MPD) with variable magnetic field

Area of Science:

• Plasma Physics
• Magnetic Confinement Fusion
• Astrophysical Plasma Dynamics

Background:

• Controlling plasma magnetization and gradients is crucial for understanding complex plasma phenomena.
• Existing devices often lack fine control over magnetized/unmagnetized plasma fractions and profile gradients.

Purpose of the Study:

• To construct and characterize a new multi-line cusp magnetic field device.
• To enable experimental control over magnetized and unmagnetized plasma volume fractions.
• To investigate plasma parameter gradients in a controlled laboratory setting.

Main Methods:

• Construction of a multi-line cusp magnetic field device using electromagnets.
• Generation of argon plasma using a hot tungsten cathode over a wide pressure range (5 × 10^-5 -1 × 10^-3 mbar).
• Radial profiling of plasma density, electron temperature, and electrostatic fluctuations using Langmuir probes.

Main Results:

• Achieved plasma densities from 10⁹ to 10¹¹ cm^-3 and electron temperatures of 1-8 eV.
• Identified a quiescent, unmagnetized plasma region with <1% electrostatic fluctuations.
• Observed magnetized plasma regions with density and temperature gradients beyond the unmagnetized zone.

Conclusions:

• The developed device offers precise control over plasma magnetization and gradient scales.
• The device facilitates the exploration of new physics in laboratory and astrophysical plasma regimes.
• The low fluctuation levels in the unmagnetized region are ideal for fundamental plasma studies.