Effects of steady state adiabatic convection on the configuration of the near‐Earth plasma sheet, 2

We have constructed two new two‐dimensional equilibrium magnetic field models for the Earth's magnetotail, in which flux tubes have nearly constant pV 5/3 between the outer boundary of the Alfvén layers and 36 R E geocentric distance. These models, corresponding to different values of pV 5/3 , are constructed for magnetospheres with rectangular magnetopauses and nonflaring tails. These results thus confirm the speculation made in our earlier paper (Hau et al., 1989) that, within the limit of ideal MHD, there exists a family of steady state convection solutions, corresponding to various degrees of magnetotail inflation. Like our previous steady state solution, each of these models also exhibits a broad minimum in equatorial magnetic field strength B ze tailward of the inner edge region between 10 and 20 R E . However, these new steady state magnetic field models possess higher values of flux tube content pV 5/3 and thus have more stretched tail configurations and smaller minimum values of B ze than those in the original model. For a model that has B ze / B lobe ≈ 0.15 at 36 R E , which is close to observed averages, the ratio B ze / B lobe is about 0.029 at 13 R E .