• Clicking on the title will open a new window with all details of the bibliographic entry.
  • Clicking on the DOI link will open a new window with the original bibliographic entry from the publisher.
  • Clicking on a single author will show all publications by the selected author.
  • Clicking on a single keyword, will show all publications by the selected keyword.

Found 2 entries in the Bibliography.

Showing entries from 1 through 2


Pulsating proton aurora caused by rising tone Pc1 waves

We found rising tone emissions with a dispersion of \~1 Hz per several tens of seconds in the dynamic spectrum of a Pc1 geomagnetic pulsation (Pc1) observed on the ground. These Pc1 rising tones were successively observed over \~30 min from 0250 UT on 14 October 2006 by an induction magnetometer at Athabasca, Canada (54.7\textdegreeN, 246.7\textdegreeE, magnetic latitude 61.7\textdegreeN). Simultaneously, a Time History of Events and Macroscale Interactions during Substorms panchromatic (THEMIS) all-sky camera detected pulsations of an isolated proton aurora with a period of several tens of seconds, \~10\% variations in intensity, and fine structures of 3\textdegree in magnetic longitudes. The pulsations of the proton aurora close to the zenith of ATH have one-to-one correspondences with the Pc1 rising tones. This suggests that these rising tones scatter magnetospheric protons intermittently at the equatorial region. The radial motion of the magnetospheric source, of which the isolated proton aurora is a projection, can explain the central frequency increase of Pc1, but not the shorter period (tens of seconds) frequency increase of \~1 Hz in Pc1 rising tones. We suggest that EMIC-triggered emissions generate the frequency increase of Pc1 rising tones on the ground and that they also cause the Pc1 pearl structure, which has a similar characteristic time.

Nomura, R.; Shiokawa, K.; Omura, Y.; Ebihara, Y.; Miyoshi, Y.; Sakaguchi, K.; Otsuka, Y.; Connors, M.;

Published by: Journal of Geophysical Research: Space Physics      Published on: 02/2016

YEAR: 2016     DOI: 10.1002/2015JA021681

EMIC-triggered waves; Pc1 waves; proton aurora


Evolution of nightside subauroral proton aurora caused by transient plasma sheet flows

While nightside subauroral proton aurora shows rapid temporal variations, the cause of this variability has rarely been investigated. Using well-coordinated observations by the Time History of Events and Macroscale Interactions during Substorms (THEMIS) all-sky imagers, THEMIS satellites in the equatorial magnetosphere, and the low-altitude NOAA 17 satellite, we examined the rapid temporal evolution of subauroral proton aurora in the premidnight sector. An isolated proton aurora occurred soon after an auroral poleward boundary intensification that was followed by an auroral streamer reaching the equatorward boundary of the auroral oval. Three THEMIS satellites in the magnetotail detected flow bursts and one of the THEMIS satellites in the outer plasmasphere observed a ring current injection together with electromagnetic ion cyclotron wave intensifications. Proton auroral brightenings occurred multiple times throughout the storm main phase and a majority of those were correlated with auroral streamers reaching the auroral equatorward boundary. This sequence highlights the important role of transient flow bursts and particle injections for plasma transport into the inner magnetosphere and thus reflects a tail-inner magnetospheric interaction process in which transient flow bursts play an important role in injecting ring current ions into the plasmasphere, causing rapid modulation of precipitation and the resultant subauroral proton aurora.

Nishimura, Y.; Bortnik, J.; Li, W.; Lyons, L.; Donovan, E.; Angelopoulos, V.; Mende, S.;

Published by: Journal of Geophysical Research: Space Physics      Published on: 07/2014

YEAR: 2014     DOI: 10.1002/2014JA020029

EMIC waves; plasma sheet flow burst; plasmasphere; proton aurora; THEMIS ASI; THEMIS satellite