Neutral pressure measurement in TCV tokamak using ASDEX-type pressure gauges

Area of Science:

• Plasma physics
• Fusion energy research
• Diagnostic techniques

Background:

• Understanding neutral gas distribution is crucial for magnetic confinement fusion devices.
• Plasma exhaust studies require precise measurements of neutral pressure.
• The TCV tokamak utilizes advanced diagnostic tools for plasma research.

Purpose of the Study:

• To install and validate ASDEX-type hot ionization pressure gauges (APGs) for in situ neutral pressure measurements in the TCV tokamak.
• To compare APG performance with existing Baratron pressure gauges (BPGs).
• To assess the suitability of APGs for future TCV divertor upgrades.

Main Methods:

• Calibration of APGs against BPGs across a pressure range of <1 mPa to several hundred mPa.
• Development of a correction for residual torus pressure to improve low-pressure accuracy.
• Analysis of APG and BPG measurements during plasma discharges with varying density ramp rates.

Main Results:

• APGs demonstrate a significantly faster time response compared to BPGs.
• APGs extend the measurable pressure range to lower pressures than BPGs.
• Systematically higher pressures measured by APGs are attributed to BPG limitations and neutral distribution.

Conclusions:

• APGs are validated as a successful and adequate pressure measurement technique for the TCV tokamak.
• The faster response and extended range of APGs offer significant advantages for plasma exhaust studies.
• APG technology is well-suited for upcoming TCV divertor upgrades.