The
contribution
of non-adiabatic ions to the
crosstail current in an O+
dominated thin plasma sheet
During storm-times, O+ can dominate both the pressure and
the density in the plasma sheet. Because of the contribution from ion
outflow, the plasma sheet is already oxygen rich prior to substorm
onset. At substorm onset, the O+ contribution increases, both due to
the energization of the O+ ions, and due to the loss of the H+ ions. In
the O+ dominated thin current sheet, the O+ ions are observed to
execute Speiser-type serpentine orbits across the tail. We calculate
the current contribution from these ions, and find that they carry
about 5-10 % of the cross-tail current. During a non-stormtime
substorm, the general behavior of the O+ is the same. However, because
there is less O+ present, the O+ never dominates over H+ and the
contribution to the crosstail current is even less.