The EXOS-D fluxgate magnetometer data obtained at 3000-10000 km altitude have shown that small-scale field-aligned currents always exist in large-scale region 1, region 2, cusp and polar cap current systems. Assuming that these small-scale field-aligned currents have current sheet structure, the width of current sheet is estimated to be 5-20 km at ionospheric altitude. By comparing the magnetometer data with charged particle and high frequency plasma wave date simultaneously obtained from EXOS-D, it is found that small-scale currents have one-to-one correspondence with localized electron precipitation events characterized by flux enhancement over a wide energy range from 10 eV to several keV and broadband electrostatic bursts occasionally extending above local plasma frequencies or electron cyclotron frequencies.
Geophysical Research Letters
- Pub Date:
- February 1991
- Ionosphere: Particle precipitation;
- Magnetospheric Physics: Current systems;
- Magnetospheric Physics: Energetic particles;
- Magnetospheric Physics: Magnetosphere/ionosphere interactions