Measurements of radial profiles of ion cyclotron resonance heating on the Tandem Mirror Experiment-Upgrade

Technical Report · Wed May 11 04:00:00 EDT 1988

DOI:https://doi.org/10.2172/7185080· OSTI ID:7185080

Falabella, S

A small Radial Energy Analyzer (REA) was used on the Tandem Mirror Experiment-Upgrade (TMX-U), at Lawerence Livermore National Laboratory, to investigate the radial profiles of ion temperature, density, and plasma potential during Ion Cyclotron Resonance Heating (ICRH). The probe has been inserted into the central-cell plasma at temperatures of 200 eV and densities of 3 x 10/sup 12/cm/sup /minus 3// without damage to the probe, or major degradation of the plasma. This analyzer has indicated an increase in ion temperature from near 20 eV before ICRH to near 150 eV during ICRH, with about 60 kW of broadcast power. The REA measurements were cross-checked against other diagnostics on TMX-U and found to be consistent. The ion density measurement was compared to the line-density measured by microwave interferometry and found to agree within 10 to 20%. A radial intergral of n/sub i/T/sub i/ as measured by the REA shows good agreement with the diamagnetic loop measurement of plasma energy. The radial density profile is observed to broaden during the RF heating pulses, without inducing additional radial losses in the core plasma. The radial profile of plasma is seen to vary from axially peaked, to nearly flat as the plasma conditions carried over the series of experiments. To relate the increase in ion temperature to power absorbed by the plasma, a power balance as a function of radius was performed. The RF power absorbed is set equal to the sum of the losses during ICRH, minus those without ICRH. This method accounts for more than 70% of the broadcast power using a simple power balance model. The measured radial profile of the RF heating was compared to the calculations of two codes, ANTENA and GARFIELD, to test their effectiveness as predictors of power absorption profiles for TMX-U. 62 refs., 63 figs., 7 tabs.

• Research Organization: Lawrence Livermore National Lab., CA (USA)
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 7185080
• Report Number(s): UCRL-53870; ON: DE88013164
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700101* -- Fusion Energy-- Plasma Research-- Confinement
Heating
& Production
COMPUTER CODES
DATA ACQUISITION SYSTEMS
DATA ANALYSIS
EFFICIENCY
ENERGY BALANCE
ENERGY LOSSES
HEATING
HIGH-FREQUENCY HEATING
ICR HEATING
ION TEMPERATURE
LEAST SQUARE FIT
LOSSES
MAGNETIC FIELDS
MAGNETIC MIRRORS
MAXIMUM-LIKELIHOOD FIT
MODIFICATIONS
NUMERICAL SOLUTION
OPEN PLASMA DEVICES
PLASMA DIAGNOSTICS
PLASMA HEATING
POWER LOSSES
RF SYSTEMS
SPACE CHARGE
TANDEM MIRRORS
TEMPERATURE DISTRIBUTION
THERMONUCLEAR DEVICES