Search Publications
Fluvial sedimentary deposits on Mars: Ancient deltas in a crater lake in the Nili Fossae region
Head, James W.; Fassett, Caleb I.
New spacecraft observations in the Nili Fossae region of Mars reveal two valley networks (~80 and ~200 km long) that each formed distributary fans as they entered an ancient 40-km diameter impact crater. An outlet channel on the eastern crater rim, lying at an elevation above the fans, suggests these fans formed as subaqueous deltas in a crater la…
The October 28, 2003 extreme EUV solar flare and resultant extreme ionospheric effects: Comparison to other Halloween events and the Bastille Day event
Tsurutani, B. T.; Didkovsky, L.; Judge, D. L. +16 more
Some of the most intense solar flares measured in 0.1 to 0.8 nm x-rays in recent history occurred near the end of 2003. The Nov 4 event is the largest in the NOAA records (X28) and the Oct 28 flare was the fourth most intense (X17). The Oct 29 flare was class X7. These flares are compared and contrasted to the July 14, 2000 Bastille Day (X10) even…
Dimensional analysis of observed structures using multipoint magnetic field measurements: Application to Cluster
Balogh, A.; Zhang, H.; Zong, Q. -G. +6 more
A new method is described to analyze the dimensional character of observed structures using multipoint magnetic field measurements of four or more spacecraft. The technique can provide three directions along which the magnetic field has the minimum, intermediate, and maximum derivatives if the magnetic gradient tensor G = $\nabla$$\vec{B at every …
Cluster encounter of a magnetic reconnection diffusion region in the near-Earth magnetotail on September 19, 2003
Balogh, A.; Rème, H.; Mouikis, C. +7 more
We report a clear encounter by the Cluster spacecraft of a magnetic reconnection diffusion region in the near-Earth magnetotail at XGSM = -17.5 RE on September 19, 2003. In addition to the reversals of the plasma jets and of GSM-z (~normal) component of the magnetic field, clear signatures of Hall quadrupolar (GSM-y) magnetic…
Evidence for rotationally driven plasma transport in Saturn's magnetosphere
André, N.; Lewis, G. R.; Coates, A. J. +7 more
Radial convective transport of plasma in a rotation-dominated magnetosphere implies alternating longitudinal sectors of cooler, denser plasma moving outward and hotter, more tenuous plasma moving inward. The Cassini Plasma Spectrometer (CAPS) has provided dramatic new evidence of this process operating in the magnetosphere of Saturn. The inward tr…
Observations of multiple X-line structure in the Earth's magnetotail current sheet: A Cluster case study
Balogh, A.; Dandouras, I.; Eastwood, J. P. +7 more
Observations of the Earth's magnetotail made by the four Cluster spacecraft on October 2 2003 are presented. Multi-spacecraft analysis is used to show that the variations in field and flow observed in the vicinity of the magnetotail current sheet are most consistent with a series of two active reconnection sites bounding an Earthward moving flux r…
Solar source of the largest geomagnetic storm of cycle 23
Howard, R. A.; Gopalswamy, N.; Michalek, G. +3 more
The largest geomagnetic storm of solar cycle 23 occurred on 2003 November 20 with a Dst index of -472 nT, due to a coronal mass ejection (CME) from active region 0501. The CME near the Sun had a sky-plane speed of ~1660 km/s, but the associated magnetic cloud (MC) arrived with a speed of only 730 km/s. The MC at 1 AU (ACE Observations) had a high …
Energetic ion acceleration in Saturn's magnetotail: Substorms at Saturn?
Krupp, N.; Dougherty, M. K.; Krimigis, S. M. +11 more
The Magnetospheric Imaging Instrument (MIMI) Ion and Neutral Camera (INCA) on the Cassini spacecraft has recorded abrupt increases in energetic neutral atom flux coming from the general direction of Saturn's magnetotail. These bursts of ion activity in the tail are well correlated with enhancements in the Saturn kilometric radiation. Given the sim…
Energetic particle injections in Saturn's magnetosphere
Krupp, N.; Krimigis, S. M.; Mitchell, D. G. +9 more
Measurements from the Cassini Magnetospheric Imaging Instrument (MIMI) beginning in July 2004 reveal that sudden planetward injections of energetic ions (5-200 keV) and electrons (20-200 keV) over confined regions of azimuth are pervasive events in Saturn's magnetosphere over the radial range of 3.8 to 11.2 Saturn radii (RS). Saturn is …
Properties of local plasma injections in Saturn's magnetosphere
André, N.; Coates, A. J.; Kurth, W. S. +6 more
Electron and ion drift dispersion events are often observed by the Cassini Plasma Spectrometer (CAPS) in the inner magnetosphere of Saturn (5 to 10 RS). These events appear to result from azimuthally-limited injections of plasma and persist for at least several hours. During this time, the events can be analyzed to obtain information on…