5-D simulation study of suprathermal electron transport in non-axisymmetric plasmas

ECRH driven transport of suprathermal electrons is studied in non-axisymmet ric plasmas using a new Monte Carlo simulation technique in 5-D phase space . Two different phases of the ECRH driven transport of suprathermal electro ns can be seen. The first is a rapid convective phase due to the direct rad ial motion of trapped electrons and the second is a slower phase due to the collisional transport. The important role of the radial transport of supra thermal electrons in the broadening of the ECRH deposition profile in W7-AS is clarified. The ECRH driven flux is also evaluated and considered in rel ation to the 'electron root' feature recently observed in W7-AS. It is foun d that, at low collisionalities, the ECRH driven flux due to the supratherm al electrons can play a dominant role in the condition of ambipolarity, and thus the observed electron root feature in W7-AS is thought to be driven b y the radial (convective) flux of ECRH generated suprathermal electrons. A possible scenario for this type of electron root is considered for the LHD plasma.