A NEW TIME CONSTANT IN ASDEX DETERMINING THE OH CONFINEMENT
The transient response of the stored energy to density variations is studied in ASDEX ohmic discharges. It is found that the phase delay between the stored energy to the density variations, tau-"rm r""rm w", is much smaller than the energy confinement time, tau-"rm E", in the density regime where tau-"rm E" scales like the Alcator scaling (=n-"rm e"< =n-"rm c"). The phase delay tau-"rm r""rm w" increases dramatically in the high density regime where tau-"rm E" saturates with density (=n-"rm e"> =n-"rm c"). The phase delay tau-"rm r""rm w" associated with density increase by pellet injection is small for operation at both high and low density. The value observed with pellet injection is as short as that seen in the low density gas puffing regime. Examination of this new time scale, tau-"rm r""rm w", may help to understand the hidden physics processes in ohmically heated plasmas. The phase delay of the central electron temperature, tau-"rm r""rm T", to density variations is observed to be small compared to tau-"rm E" at all densities.
Bibliographic Reference: WRITE TO MAX-PLANCK-INSTITUT FUER PLASMAPHYSIK, 8046 GARCHING BEI MUENCHEN (GERMANY), MENTIONING REPORT IPP III/133, 1988
Record Number: 1989126108600 / Last updated on: 1989-06-01
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