Development of a diamagnetic loop in KAIMIR

Area of Science:

• Plasma Physics
• Magnetic Confinement Fusion

Background:

• Diamagnetic loops are crucial for estimating plasma stored energy by measuring diamagnetic flux.
• Vacuum flux often overwhelms diamagnetic signals, necessitating advanced noise reduction techniques.
• High signal-to-noise ratio is critical for accurate diamagnetic flux measurements.

Purpose of the Study:

• To develop an improved diamagnetic loop system for accurate plasma stored energy estimation.
• To significantly reduce background noise and enhance the signal-to-noise ratio in measurements.
• To validate the developed system against established diagnostic methods.

Main Methods:

• Utilized two identical diamagnetic loops with opposite polarities to cancel parasitic capacitive noise and amplify inductive signals.
• Employed two coaxial loops of different radii at the same axial location to eliminate vacuum flux.
• Configured six paired loops to ensure robust noise and vacuum flux suppression.

Main Results:

• Successfully removed parasitic capacitive noise, amplifying the inductive signal twofold.
• Effectively eliminated vacuum flux through the coaxial loop configuration.
• Demonstrated excellent agreement between plasma stored energy measurements from the developed diamagnetic loop and Langmuir probe data.

Conclusions:

• The novel diamagnetic loop system provides accurate plasma stored energy measurements in magnetic mirror devices.
• The employed noise reduction and vacuum flux elimination techniques significantly improve diagnostic reliability.
• This advancement offers a more precise tool for understanding plasma behavior in fusion research.