dn( +13+12 d v. av. av a√r exp 3k T Known v C dn(vr, vy, v)3 whule C N 2( ) exp d d d 1 d ( , , ) 2 2 2 2 3 x y z x y z x y z v v v v v v N n v v v         + + −          =    = ? m k T v 3 2 B Known = 2 2 2 2 d ( , , ) 3  =    = N n v v v v v while x y z