Cross field transport of electrons

Early studies of electron transport in crossed E and B fields have been reviewed and applied to the case of a positive surface moving in the ionosphere. That work points to the importance of the parameter q = omega p2/omega c2 in determining self consistent spacecharge distributions in cross field diodes, and similarly, a crossed field probe plasma sheath in non linear, non adiabatic limits. The application of existing theory to the problem of electron collection by a surface aligned with B indicates that for q> 1/2 the plasma sheath is only slightly perturbed by B, but for q <1/2 the sheath cannot form without electrons transported along B from the ends.