Low-energy x-ray emission from magnetic-fusion plasmas

Technical Report · Thu Apr 01 00:00:00 EST 1982

DOI:https://doi.org/10.2172/5328728· OSTI ID:5328728

Hill, K W; Bitter, M; Eames, D; von Goeler, S; Goldman, M; Sauthoff, N R; Silver, E

Complex, transient, spatially inhomogeneous tokamak plasmas require careful diagnosis. As the reactor regime is approached, soft x rays become more important as a versatile diagnostic tool and an energy-loss mechanism. Continuum emission provides a measure of electron temperature and light impurity content. Impurity lines serve as a probe for ion and electron temperature, impurity behavior, and radiative cooling. The entire spectrum yields vital information on instabilities and disruptions. The importance of impurities is illustrated by the extensive efforts toward understanding impurity production, effects, and control. Minute heavy impurity concentrations can prevent reactor ignition. Si(Li) - detector arrays give a broad overview of continuum and line x-ray emission (.3 to 50 keV) with moderate energy (200 eV) and time (50 ms) resolution. Bragg crystal and grating spectrometers provide detailed information on impurity lines with moderate to excellent (E/..delta..E = 100 to 23,000) resolving power and 1 to 50 ms time resolution. Imaging detector arrays measure rapid (approx. 10 ..mu..s) fluctuations due to MHD instabilities and probe impurity behavior and radiative cooling. Future tokamaks require more diagnostic channels to avoid spatial scanning, higher throughput for fast, single-shot diagnosis, increased spectral information per sample period via fast scanning or use of multi-element detectors with dispersive elements, and radiation shielding and hardening of detectors.

• Research Organization: Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
• DOE Contract Number: AC02-76CH03073
• OSTI ID: 5328728
• Report Number(s): PPPL-1887; ON: DE82009817; TRN: 82-011949
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
PLASMA DIAGNOSTICS
X-RAY SPECTRA
TOKAMAK DEVICES
ELECTRON TEMPERATURE
IMPURITIES
INHOMOGENEOUS PLASMA
PLASMA
PROBES
SOFT X RADIATION
CLOSED PLASMA DEVICES
ELECTROMAGNETIC RADIATION
IONIZING RADIATIONS
RADIATIONS
SPECTRA
THERMONUCLEAR DEVICES
X RADIATION
700102* - Fusion Energy- Plasma Research- Diagnostics