961). 29. Following (341, balancing the Lorentz force and the rate of ion-neutral collisions gives ev, X B = m,vi,(v, -v,), where v, and v, are the ion and neutral velocity vectors. Solving for the vertical component of ion velocity yields wi = (u cosl cosD)lq for u > > v, w, the meridional and vertical components of the neutral wind, and T, >> I. Differentiating with respect to z, where H, is the scale height of the neutral atmosphere. The expressions vi , = 2~(a"e~/~")"~ n and Ci = eB/mi are

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... rom (6). 30. The upward wind is usually attributed to E X B drift; in this case, the magnitude of the electric field (E) component perpendicular to B and z is E,w,Bl cosl = 0.