Mirror Confined Plasma in the Large Helical Device

Detailed stracture of the magnetic field in the Large Helical Deveice (LHD) is studied numerically. The connection length of the divertor field line is found to be the order of several km or more. The possibility of the mirror-confined plasma in the chaotic field line region is shown. The divertor plasma model is proposed based on the long connection length and the existence of the mirror-confined plasma in the chaotic field line region. A new ICRF heating scheme (runaway ion heating scheme) for LHD is also proposed based on the existence of the mirror-confined plasma in the core plasma region.