Quasi-monochromatic ULF foreshock waves as observed by the four-spacecraft Cluster mission: 2. Oblique propagation

Pc3–4 ULF waves observed by the SuperDARN TIGER radar

Despite extensive research, the mechanisms for propagation of Pc3–4 energy from the generation region at the bow shock to the high-latitude ionosphere remain unresolved. We used high temporal (6–12 s) and spatial (45 km) resolution data from the SuperDARN TIGER radar (Tasmania) to examine Pc3–4 wave signatures at the F-region heights. We focus on a case study on 28 September 2000, when large-am...

Propagation of ULF waves through the ionosphere: Inductive effect for oblique magnetic fields

Solutions for ultra-low frequency (ULF) wave fields in the frequency range 1–100 mHz that interact with the Earth’s ionosphere in the presence of oblique background magnetic fields are described. Analytic expressions for the electric and magnetic wave fields in the magnetosphere, ionosphere and atmosphere are derived within the context of an inductive ionosphere. The inductive shielding effect ...

Anomalous foreshock field-aligned beams observed by Cluster

We report occasional observations of two simultaneously distinct ion foreshock components recorded by the Cluster spacecraft upstream of the Earth’s bow shock. In most occurrences, the lower-energy population originates as a field-aligned beam (FAB) associated with quasiperpendicular regions, which loses energy as the IMF rotates into oblique geometries. A second beam, with energies in excess o...

Plasma flow channels with ULF waves observed by Cluster and Double Star

On 14 August 2004 a large-scale magnetic structure was observed by Double Star TC-1 in the southern lobe and by Cluster in the northern lobe of the magnetotail. The structure has the signature of a (localized) dipolarization, decreasing Bx accompanied by an increasing Bz and a strong earthward flow. The propagation direction of this structure, however, seems to be more in the dawnward direction...

Whistlers observed by the Cluster spacecraft outside the plasmasphere