Abstract
Rapid (<1 s) intensity modulation of pulsating auroras is caused by successive chorus elements as a response to wave-particle interactions in the magnetosphere. Here we found that a pulsating auroral patch responds to the time spacing for successive chorus elements and possibly to chorus subpacket structures with a time scale of tens of milliseconds. These responses were identified from coordinated Arase satellite and ground (Gakona, Alaska) observations with a high-speed auroral imager (100 Hz). The temporal variations of auroral intensity in a few-hertz frequency range exhibited a spatial concentration at the lower-latitude edge of the auroral patch. The spatial evolution of the auroral patch showed repeated expansion/contraction with tens of kilometer scales in the ionosphere, which could be spatial behaviors in the wave-particle interactions. These observations indicate that chorus elements evolve coherently within the auroral patch, which is approximately 900 km in the radial and longitudinal directions at the magnetic equator.
| Original language | English |
|---|---|
| Pages (from-to) | 12,125-12,134 |
| Journal | Geophysical Research Letters |
| Volume | 45 |
| Issue number | 22 |
| DOIs | |
| Publication status | Published - 28 Nov. 2018 |
Keywords
- Arase satellite
- discrete chorus element
- ground-based observation network
- pulsating aurora
- wave-particle interaction