RF STARTUP IN THE PHAEDRUS AND PHAEDRUS-B TANDEM MIRRORS

A new method for producing plasma buildup in a tandem mirror was developed. A cold (;The STARTUP point code was created to model the ICRF induced plasma buildup. ICRF heating of the ions and electrons as a function of plasma density, ion temperature, and electron temperature was included in the modeling. Heating rates were calculated using the RF fields code ANTENA. Density buildup predicted by the STARTUP code for different neutral pressure levels was observed to agree qualitatively with experimental measurements.;Analysis of STARTUP code results indicated that ;The plasma buildup under the influence of the ICRF heating was investigated. It was found that direct electron heating by the ICRF played a crucial role. It was also determined that ECH generated hot electrons were not required for successful plasma buildup. An important finding was that the buildup was inhibited or totally prevented when the initial electron temperature was too low. This condition occurred at high neutral pressure levels, or low ECH power levels.