ISSN:
1089-7623
Source:
AIP Digital Archive
Topics:
Physics
,
Electrical Engineering, Measurement and Control Technology
Notes:
The precise measurement of the power absorption in some ECRH plasma experiments can be plagued with many practical problems, which makes the direct validation of any theoretical model difficult. In the present work, the feasibility of a method to directly measure the electric field at the predicted resonant position is carried out. From the electric field it is possible to compute the local density power carried by the microwave beam and, hence, deduce the power deposition profile. The method based on measuring the ratio of near and far satellite intensities of He I lines, already used in cold plasma discharges,1 presents challenging problems when applied to a hotter plasma. The electric field is estimated using ray tracing calculations in the TJ-IU torsatron. The field is locally obtained in the plasma from the dispersion relation and the estimations for the injected power (200 kW) show that the effect of the microwave field can be non-negligible on the He I lines. An experimental setup to explore this idea in the TJ-IU torsatron will be described. The low densities of this device and the use of a signal-to-noise subtraction technique make this method feasible according to our preliminary estimation. The difficulties encountered and the results obtained will be reported.© 1997 American Institute of Physics.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.1147616
