Any help on the following theoretical plasma problem would be greatly appreciated! The diffusion eqn for a one-dimensional plasma, varying in the x direction only is D d^{2}n/dx^{2} =-Q Letting Q=nv_{i} we can show the diffusion eqn has a solution of the form n=Asin[sqrt(v_{i}/D)x] + Bcos[sqrt(v_{i}/D)x] Supposing boundary conditions of plasma are set at x= +/- L/2 where n=0 and x=0 where n=n_{0} one can show n=n_{0}cos(x pi/L) The bit I am finding trouble with is what the implications of sqrt(v_{i}/D)=pi/L are with respect to the electron temperature T_{e}, I have recalled that v_{i} has an exponential dependence on T_{e} but cannot reason what this means. Many thanks in advance for any help.