Alpha-particle losses due to pitch-angle scattering into the loss cone of an open-field-line configuration are investigated. Specifically, the particle loss and the corresponding energy loss are given as explicit functions of energy during slowing-down. It is found that the alpha-particle energy loss due to pitch-angle scattering for a pure DT-plasma is of the order of 5–10%, in contrast to the 35–40% obtained in a recent paper

One-dimensional model for nonlinear reflection of laser radiation by an inhomogeneous plasma layer.

An investigation is made of the heat transport equation T, = (l/r)(rKT,.)r where the thermal conductivity, K , is of the form K -rYTn (T being temperature and r radial coordinate). The analysis presents a systematic way to obtain analytic approximations for the radial temperature profile and the decay time of the temperature, in good agreement with numerical calculations. The results are applied to several thermal energy transport models for magnetically confined plasmas.

The dynamic response of a burning fusion plasma to periodic particle source fluctuations as well as to self-induced or externally induced fluctuations in the transport coefficients is studied. Simple coupled reaction-diffusion equations are deduced for the dynamic description of the time variation of the temperature and density in the central part of the plasma. As a result of the form of the alpha particle heating term such a system of equations exhibits free oscillations in temperature and density in approaching an equilibrium state from any given initial state. When the particle sources or the transport coefficients are asumed to have driven periodic parts the plasma responds dynamically by exhibiting a mixture of free and forced oscillations. Since, due to heat conduction and particle diffusion, the free oscillations will be damped, only the forced oscillations remain after some time. The plasma dynamic response to the driven variations in the source and transport coefficients contains information about the plasma transport parameters, e.g. the power of the temperature dependence of the heat conductivity as well as of the particle diffusion. It might therefore be used for diagnostics for a burning fusion plasma.

Intense, very coherent electromagnetic radiation can, in principle, be generated by the interaction of a relativistic electron beam and a molecular medium in the presence of a wiggler field (or a strong electromagnetic pump wave). Enhanced spatial growth in a narrow frequency region results from the presence of the molecules as demonstrated in graphs from computer calculations. These effects are found to occur when the molecules (or ions) have inverted populations, i.e., for maser or laser media, as well as for situations where this is not the case, i.e., when the molecules act like micro-cavities (passive resonators), distributed over the volume of interaction.