FAST-WAVE MINORITY HEATING IN AN OPEN TRAP

A light ion minority heating scheme based on long wavelength fast magn etosonic wave (FMSW) global resonance excitation appears to be promisi ng for open traps. This scheme has been studied numerically using the 2-D code PLFEM. This code uses both local and non-local approximations and can search for global resonances. The global FMSW resonance width (TE1,0,2 mode), which is caused by hydrogen minority cyclotron energy absorption, is found to be a maximum for a minority concentration of C(H) = 1-2%. For these concentration values a substantial discrepancy between the local and non-local approximations occurs. This discrepenc y is a result of local Alfven resonance excitation in the vicinity of the hydrogen cyclotron zone in a cold plasma. The Alfven resonance dis appears when even a slight thermal motion of the ions (non-locality) i s taken into account. By proceeding with global resonance field patter ns, a suitable antenna system consisting of two loops fed with opposit e phases has been chosen. Calculations have demonstrated that this ant enna system has good electrotechnical qualities.