ULF-Waves on the Ground and in Space - Hydromagnetic Waves in the Magnetosphere and the Ionosphere - page 65

Fig. 3.14. CRRES and Kakioka ( L =1 . 26) data for the selected Pi 2events.The
CRRES field components are respectively B ρ : radial; B ϕ : azimuthal, positive east-
ward; B z : northward. The CRRES E ϕ electric field component is dusk-to-dawn. Bot-
tom: The Kakioka magnetic field. After [99]
Multisatellite observations of substorm onsets on the nightside at 4 <
L< 7 revealed transversal waves with frequency depending on L that can
be attributed to the FLR. About 30% of the Pi 2eventsontheEarthare
accompanied by nightside toroidal pulsations [98].
Analysis of low latitude magnetic data from the Combined Release and
Radiation Effects Satellite (CRRES) and at low latitude station Kakioka
( L =1 . 26) shows that the Pi 2 pulsations appear when both CRRES and
Kakioka were on midnight. At CRRES the pulsations were detected in the
FMS-mode. An example of the Pi 2 pulsations simultaneously observed in
space and on the ground is shown in Fig. 3.14 [99].
Using one of the reference works by Anderson [1], we cite only the tabulated
results of observations of MHD-waves in the magnetosphere. Basing the clas-
sification of magnetospheric perturbations on their periods and polarizations,
Anderson distinguishes 6 pulsation types: compressional Pc 5, poloidal Pc 4,
compressional Pc 3, toroidal field line harmonics, toroidal Pc 5 and incoher-
ent noise (see Table 3.1). Here b ν ,b , and b ϕ mark, respectively, the radial,
longitudinal and azimuthal magnetic components.
Notes:
1. Compressional Pc 3 , 4 relate to wave-particle interaction in the foreshock
and shock.
2. Toroidal Pc 3 , 4 or multi-harmonics are field line resonance harmonics in
Pc 3 , 4 range. Compressional Pc 3 , 4 is a driver (coupling with the funda-
mental toroidal mode).