PPPL-3650 is available in <a href="PPPL-3650.pdf">pdf</a> format.

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<b>Mechanisms of Stochastic Diffusion of Energetic Ions in Spherical Tori
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<b>Authors:</b> Ya.I. Kolesnichenko, R.B. White, and Yu.V. Yakovenko  
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<b>Date of PPPL Report:</b> January 2002
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<b>Submitted to:</b> Physics of Plasmas </p>


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Stochastic diffusion of the energetic ions in spherical tori is considered. The following issues are addressed: (i) Goldston-White-Boozer diffusion in a rippled field; (ii) cyclotron-resonance-induced diffusion caused by the ripple; (iii) effects of non-conservation of the magnetic moment in an axisymmetric field. It is found that the stochastic diffusion in spherical tori with a weak magnetic field has a number of peculiarities in comparison with conventional tokamaks; in particular, it is characterized by an increased role of mechanisms associated with non-conservation of the particle magnetic moment. It is concluded that in current experiments on National Spherical Torus eXperiment (NSTX) the stochastic diffusion does not have a considerable influence on the confinement of energetic ions.




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