Direct losses of fast ions are investigated numerically in current multiple-toroidicity stellarator configurations, in which magnetic field harmonic spectra can be described adequately by a sum of hundreds harmonics with different toroidal and poloidal mode numbers. For these configurations it is typical that amplitudes of distant harmonics with high-order N greater than or equal to2 toroidal mode numbers can exceed, near the plasma boundary, one-half of the amplitude of the main magnetic-field harmonic. This leads to the appearance of additional ripple wells along field lines which can trap charged particles (toroidally field ripple-trapped particles). An investigation of the role of these particles in plasma confinement in stellarators is the main goal of the paper. It is shown that a complication of the magnetic-field harmonic spectrum of a stellarator causes direct losses of transition and toroidally field ripple-trapped particles several times higher than losses of corresponding particles in rippled tokamaks. (C) 2001 American Institute of Physics. [References: 36]
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