A. Greco et al., Numerical simulation of ion dynamics in the magnetotail magnetic turbulence: on collisionless conductivity, NONL PR GEO, 7(3-4), 2000, pp. 159-166
The ion dynamics in the distant Earth's magnetotail is studied in the case
that a cross tail electric field and reconnection parity magnetic turbulenc
e are present in the neutral sheet. A test particle simulation is performed
for the ions, and moments of the ion distribution function are obtained as
a function of the magnetic fluctuation level, delta B/B-0, and of the valu
e of the cross tail electric field, E-y. It is found that magnetic turbulen
ce can split the current carrying region into a double current sheet, in ag
reement with inferences from observations in the distant magnetotail. The p
roblem of ion conductivity is addressed by varying the value of the cross t
ail electric field from zero to the observed one: we find that Ohm's law is
not enforced, and that a non local, system dependent conductivity is neces
sary to describe the ion response to the electric field. Also, it appears t
hat the relation between current and electric field may be nonlinear.