Observation of Ion Confining Potential Enhancement due to Thermal Barrier Potential Formation and Its Scaling Law in the Tandem Mirror GAMMA 10

In the tandem mirror GAMMA 10 , (i) the enhancement of the ion confining potential, φ c , only during the period of the thermal barrier potential φ b -formation, has been observed first by using not only end-loss-analysers ( ELA 's) of GAMMA 10 but an end-loss-ion-spectrometer ( ELIS ) installed from TMX-U . This results in strong end-loss-ion plugging with increased central cell density. (ii) The first experimental observation of the φ c vs φ b -scaling law is obtained, where φ c increases with φ b . This scaling law is consistently interpreted by Cohen's theories of tlte weak- ECH and the strong- ECU in the plug region, (iii) Good agreement of the plug potential measuredwith the ELA 's and the ELIS is achieved.