ULF-Waves on the Ground and in Space - Hydromagnetic Waves in the Magnetosphere and the Ionosphere - page 56

MAGNETOSPHERIC PLASMA

Β

Magnetopause

High pressure Low pressure

Magnetosheath

.

SOLAR WIND PLASMA

Magnetosphere

MAGNETOSPHERIC PLASMA

φ

A

p

C

Β

Magnetopause

φ

2

High pressure Low pressure ∂ φ

−

2

∂ ϕ

.

SOLAR WIND PLASMA

φ

(a) (b)

Fig. 3.7. Suggested scenario in which the large changes in the solar wind dynamic
pressure produces a unipolar FAC proportional to the azimuthal derivative of the
pressure perturbations (a) After Glassmeier et al. (1989). (b) A stepwise pressure
change and a bipolar system of FAC is proportional to the second derivative of the
pressure perturbation. After Kivelson and Southwood (1991)

eastern stations which corresponds to the tailward motion of the convective
perturbation.
The equivalent current system constructed from these data and supple-
mented by records from the Greenland station chain is shown in the upper

MIK

ROS

KIR

NAT

PIT

MIK

ROS

KIR

NAT

PIT

0730 0740 0740 0740 0740 0740 0740

(a) (b)

Fig. 3.8. Simultaneous NS - (upper part of panel (b)), and EW - magnetograms
(lower part) from the Scandinavian magnetometer array of stations (a) [23]