Scaling study of potential in the end region of a tandem mirror based on end-loss electron measurement.

An empirical scaling for the potential difference between the plug potential [uppercase_phi_synonym]P and the floating potential [uppercase_phi_synonym]EP of an endplate is obtained in terms of end-loss electron temperatures. Results from the GAMMA 10 tandem mirror [Phys. Rev. Lett. 55, 939 (1985)] indicate that Δ[uppercase_phi_synonym]=[uppercase_phi_synonym]P-[uppercase_phi_synonym]EP scales much better with an effective temperature Teff≡(1-β)TeL+βTeH than with a single temperature TeL or TeH, where TeL and TeH are temperatures of the bulk and the high-energy tail components of the end-loss electrons and β denotes the flux fraction of the TeH component. Moreover, the observed scaling is consistent with a recently developed theoretical model [K. Kurihara et al., J. Phys. Soc. Jpn. 61, 3153 (1992)]. [ABSTRACT FROM AUTHOR]