Installation of a solid state neutral particle analyzer array on mega ampere spherical tokamak upgrade

Area of Science:

• Plasma Physics
• Fusion Energy Research
• Diagnostic Instrumentation

Background:

• The compact solid state neutral particle analyzer (SSNPA) is a diagnostic tool crucial for understanding plasma behavior.
• This SSNPA was previously operational at the National Spherical Torus Experiment Upgrade (NSTX-U).

Purpose of the Study:

• To successfully relocate and operate the SSNPA diagnostic at the Mega Ampere Spherical Tokamak Upgrade (MAST-U).
• To diagnose the fast ion distribution in MAST-U plasma using active charge exchange (CX) signals.

Main Methods:

• The SSNPA utilizes three 16-channel sensors for a radial plasma view, intersecting with the South-South neutral beam line.
• It detects fast neutral particles produced by charge exchange (CX) reactions.
• Coarse energy resolution is achieved through varying filter thicknesses across sensors.

Main Results:

• The SSNPA was successfully operated during the first physics campaign (MU01) at MAST-U.
• All diagnostic channels functioned as intended, collecting data with a typical signal-to-noise ratio of approximately 15.
• Preliminary analysis revealed correlations between SSNPA signals and plasma magnetohydrodynamic activity.

Conclusions:

• The relocated SSNPA is a functional diagnostic for MAST-U.
• The diagnostic provides valuable insights into fast ion behavior and its relation to plasma dynamics.
• The SSNPA's performance meets expectations for plasma research at MAST-U.