Search Publications
Type II radio emissions in the frequency range from 1-14 MHz associated with the April 7, 1997 solar event
St. Cyr, O. C.; Thompson, B. J.; Kaiser, M. L. +4 more
We present an analysis of radio emissions associated with the April 7, 1997 solar eruptive event. The event consisted of a filament disappearance, a complex two-phase coronal mass ejection (CME), and a C6.9, 2N flare. At the same time, intermittent type II radio emissions in the frequency range 1-10 MHz, corresponding to an altitude range of 2-15 …
Energetic (∼ 1 to 50 MeV) protons associated with Earth-directed coronal mass ejections
Laitinen, T.; Vainio, R.; Valtonen, E. +7 more
During the period from January through mid-May, 1997, four large Earth-directed CMEs were observed by the Large Angle Spectroscopic Coronograph (LASCO). These CMEs were associated with long-lasting fluxes of >1.6 MeV protons detected by the Energetic and Relativistic Nuclei and Electron instrument (ERNE). However, the magnitudes of energetic pr…
Radial heliospheric magnetic fields detected by Ulysses
Balogh, A.; Jones, G. H.; Forsyth, R. J.
The magnetometer aboard the Ulysses spacecraft has recorded numerous examples of heliospheric magnetic fields orientated in near-radial directions for periods of several hours or more. These fields are unusual, as their existence is contrary to the predictions of classical theories concerning solar wind production and propagation. The magnetic fie…
Evidence for multiple ejecta: April 7-11, 1997, ISTP Sun-Earth connection event
Reiner, M.; Delaboudinière, J. -P.; Bougeret, J. -L. +12 more
Evidence is presented that the enhanced geomagnetic activity, on April 10-11, 1997, was caused by one of two ejecta that left the Sun at ≈ 14 UT on April 7. This ejecta was not directly detected at the Earth. The evidence for this interpretation is based on WIND spacecraft observations in the solar wind (SW). It is consistent with: (i) measured ve…
Elemental composition of the January 6, 1997, CME
Hsieh, K. C.; Wurz, P.; Bochsler, P. +25 more
Using solar wind particle data from the CELIAS/MTOF sensor on the SOHO mission, we studied the abundance of the elements O, Ne, Mg, Si, S, Ca, and Fe for the time period around the January 6, 1997, coronal mass ejection event (CME). In the interstream and coronal hole regions before and after this event we found elemental abundances consistent wit…
Do coronal mass ejections implode in the solar wind?
Riley, Pete; Gosling, J. T.
Ulysses observations show that many coronal mass ejections observed at high heliographic latitudes expand because they initially have higher internal pressures than that of the surrounding solar wind. This expansion commonly drives a shock wave into the ambient wind in all directions. In the analogous process of an explosion in the Earth's atmosph…
A pair of forward and reverse slow-mode shocks detected by Ulysses at ∼5 AU
Lakhina, G. S.; Tsurutani, B. T.; Smith, E. J. +6 more
We report the first finding of a pair of forward and reverse slow-mode shocks in the distant heliosphere using plasma and magnetic field data from the Ulysses spacecraft located at 5.3 AU and 9°S heliolatitude. The slow-mode shocks are found to occur in a compressed magnetic field (low plasma ) region within a co-rotating interaction region (CIR).…
Wind-Ulysses source location of radio emissions associated with the January 1997 coronal mass ejection
Maksimovic, M.; Kaiser, M. L.; Bougeret, J. -L. +2 more
We investigate the 3-D source location of interplanetary type Il-like radio bursts from observations involving two spacecraft. Uncommon type II radio emissions were observed simultaneously on 8 January 1997 by the Wind and Ulysses spacecraft and are believed to be associated with the Interplanetary Coronal Mass Ejection detected on 6-7 January by …
The symmetry of the heliospheric current sheet as observed by Ulysses during the Fast Latitude Scan
Balogh, André; Erdős, Géza
The position of the heliospheric current sheet is investigated, based on Ulysses observations during the fast latitude scan from the South pole (in September, 1994) to the North pole (in July, 1995). The location of the current sheet on the source surface was calculated by mapping back the magnetic field vectors measured by Ulysses along the solar…
Synoptic measurements of Martian winds using the Hubble Space Telescope
Crisp, David; Bell, James F., III; Mischna, Michael A. +1 more
We used the Hubble Space Telescope to make wind speed and wind direction measurements of the Martian atmosphere during early northern summer (Ls=97°). Our strategy utilized a series of near-UV images with optimal temporal sampling to track observable cloud features and to determine the direction and speed of cloud motion. Several techni…