The startup of an electrodeless RF discharge in toroidal systems in presence of low magnetic field

Summary form only given. Breakdown threshold voltage of an electrode less toroidal discharge has been studied using H- type solenoid coil excited by a 13.56 MHz radio frequency power in absence and in presence of a pre ionizing condition with different pressures, aspect ratio and axial magnetic field for dry air, molecular and rare gases. The breakdown threshold depends on various filling parameters, Pre-ionising condition, aspect ratio and magnetic field.