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Figure 13 | Earth, Planets and Space

Figure 13

From: Global and frequent appearance of small spatial scale field-aligned currents possibly driven by the lower atmospheric phenomena as observed by the CHAMP satellite in middle and low latitudes

Figure 13

Model of spatial latitudinal structures and graph showing dependence of the scale on dip angle. (a) A simple model of the spatial scale of the FAC along the orbits of the CHAMP satellite with use of the dipole model under the assumption that the spatial scale of the FAC source in the ionosphere shown by a symbol ‘a’ is independent of the dipole latitude. The spatial scale at the CHAMP satellite projected along the geomagnetic field line from each source ‘a’ corresponds to a symbol ‘b’ with index of the number. (b) A red dotted line shows the averaged period observed by the CHAMP satellite, as also shown in Figure 7, multiplied by the satellite velocity, i.e., 7.6 km/s. Three black lines respectively indicate spatial scales at an altitude of 400 km calculated under the assumption that the spatial scales of the current source at an altitude (100 km) are independent of latitude and set to be 20, 80, and 140 km. A green dotted line shows the spatial scale of the current source at an altitude of 100 km estimated from the observed period with use of the dipole model.

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