Plasma neutraliser for ITER NBI

The maximal neutral fraction from the passage of a D beam through a gas, as proposed for a gas neutraliser of reference ITER NBI concept, is 60%. The replacement of the gas neutraliser by a plasma one must increase the maximum neutral yield to 80%. This is an attractive improvement of the ITER NBI system. As the plasma neutraliser must be able to replace the gas neutraliser in the ITER NBI of the reference concept, its length is defined and equal to 3 meters. So, the necessary plasma density n(e) similar to 7 x 10(12) cm(-3). We assume that PN should spend less than 2 MW of electrical power per one NBI module. The multicusp 3D magnetic wall configuration seems to be the best choice for PN plasma confinement system. This system can provide the necessary plasma confinement and an acceptable deviation effect on the beam ions. The plasma will be produced in steady - state mode of operation by the electrodeless microwave discharge at gas pleasure less than 10(-4) torr at mainly collisionless character of microwave energy absorption.