High sensitivity, low noise Mirnov coil array on Prairie View rotamak

Area of Science:

• Plasma physics
• Magnetic confinement fusion

Background:

• Rotamak devices are toroidal plasma configurations driven by rotating magnetic fields.
• Understanding plasma instabilities is crucial for magnetic confinement fusion research.
• Previous diagnostics had limitations in sensitivity and noise for rotamak plasmas.

Purpose of the Study:

• To develop and implement a novel, high-sensitivity, low-noise Mirnov coil array for rotamak plasmas.
• To utilize the new diagnostic system to observe and characterize plasma instabilities.
• To advance the understanding of plasma behavior in rotamak devices.

Main Methods:

• Installation of a 32-coil B(R)-oriented Mirnov coil array on the exterior chamber surface.
• Utilizing the array to measure magnetic perturbations with a sensitivity of 0.1 G.
• Analysis of magnetic signals to identify specific plasma modes.

Main Results:

• The novel Mirnov coil array demonstrated high reliability and sensitivity in the rotating magnetic field-driven plasma.
• Magnetic perturbation signals as low as 0.1 G were successfully resolved.
• The n = 1 tilt, radial shift, and kink modes were observed for the first time in rotamak plasmas.

Conclusions:

• The new Mirnov coil array is a reliable and effective diagnostic for rotamak plasmas.
• The observed plasma modes provide new insights into rotamak stability and behavior.
• This diagnostic advancement opens new avenues for studying plasma dynamics in these devices.