Magnetic Interactions in a Warm Plasma

A comparison of several kinetic equations with electromagnetic interactions is made. In particular the effects of assuming the Darwin Hamiltonian are investigated, and it is concluded that the role of the magnetic forces may be of importance in the stability problem, since they seem to manifest tendencies opposite to those of the electrostatic forces in the limiting cases of long and short wavelengths. The possibility of the existence of density waves at or close to equilibrium, due to the presence of the ${\left(\frac{v}{c}\right)}^2$ interactions, is pointed out. Transport calculations will lead to the same results as those in the calculations of Trubnikov, although it may be expected that if cutoffs are eliminated as in previous work, the results will differ.