Search Publications
Interplanetary acceleration of coronal mass ejections
St. Cyr, O. C.; Kaiser, M. L.; Gopalswamy, N. +3 more
Using an observed relation between speeds of CMEs near the Sun and in the solar wind, we determine an “effective” acceleration acting on the CMEs. We found a linear relation between this effective acceleration and the initial speed of the CMEs. The acceleration is similar to that of the slow solar wind in magnitude. The average solar wind speed na…
Coronal dimmings and energetic CMEs in April-May 1998
Thompson, B. J.; Delaboudinière, J. -P.; Nitta, N. +2 more
We have analyzed the coronal dimmings for seven fast (> 600 km/s) coronal mass ejections (CMEs) occurring between 23 April and 9 May which were associated with flares from NOAA active region (AR) 8210. Each of these CMEs had at least one group of interplanetary radio bursts associated with them. These dimming regions were identified by their st…
SOHO and radio observations of a CME shock wave
St. Cyr, O. C.; Romoli, M.; Gopalswamy, Nat +7 more
A 1200 km s-1 Coronal Mass Ejection was observed with the SOHO instruments EIT, LASCO and UVCS on June 11, 1998. Simultaneously, Type II radio bursts were observed with the WAVES experiment aboard the Wind spacecraft at 4 MHz and by ground-based instruments at metric wavelengths. The density in the shock wave implied by the higher frequ…
Radio-rich solar eruptive events
Thompson, B. J.; Kaiser, M. L.; Burlaga, L. F. +6 more
We report on the analysis of a large number of solar eruptive events that produced radio emission in the dekameter-hectometric (DH) radio window (1-14 MHz), newly opened by the Wind/WAVES experiment. The distinguishing characteristics of coronal mass ejections (CMEs) associated with the DH type II radio bursts are larger-than-average width and spe…
Observed constraint on proton-proton relative velocities in the solar wind
Goldstein, Bruce E.; Neugebauer, Marcia; Gary, S. Peter +1 more
From June 1994 to December 1995 the Ulysses spacecraft was within 3 AU of the Sun and traveled from high southern to high northern heliospheric latitudes. For this period, SWOOPS instrument data obtained when the magnetic field was approximately aligned with the radial direction from the Sun have been analyzed. In the fast wind at high latitudes, …
Ulysses observations of the irregularly structured mid-latitude solar wind during the approach to solar maximum
McComas, D. J.; Gosling, J. T.; Skoug, R. M.
The Ulysses spacecraft reached 45°S heliolatitude in its second polar orbit on 5 February 2000. Solar wind observations over the first portion of Ulysses' second orbit have been remarkably different from those taken at mid-latitudes throughout its first orbit. During these portions of its first orbit, Ulysses crossed back and forth between the fas…
Lyman-α imaging of the SO2 distribution on Io
Ballester, Gilda E.; Wolven, Brian C.; Feldman, Paul D. +7 more
Imaging spectroscopy of Io in the ultraviolet (1160-1720 Å) was carried out with the Space Telescope Imaging Spectrograph on HST on three dates in October 1997 and August 1998. Among the initial results was the observation of concentrated regions of Hi Lyman-α flux near the poles of Io that exhibited a morphology and temporal variability different…
The latitudinal distribution of solar wind magnetic holes
Tsurutani, Bruce T.; Goldstein, Bruce E.; Neugebauer, Marcia +2 more
Using the fast latitude scan period of the Ulysses spacecraft, the occurrence of magnetic holes in the solar wind is investigated from -80° to +80° helio-latitude. Near the ecliptic, the large average value and the large variations of the hole count rate appear to be correlated with interaction regions. It is found, however, that at 30°north and s…
Slowdown of the Solar Wind in the Outer Heliosphere and the Interstellar Neutral Hydrogen Density
Wang, C.; Richardson, J. D.; Gosling, J. T.
Voyager 2 and Ulysses were at nearly the same latitude in the southern heliosphere at the beginning of 1999 and their radial separation was about 55 AU. The effect of pickup ions should be profound at Voyager's position, especially, the deceleration of the solar wind flow. This unique opportunity allows us to investigate the effect of pickup ions …
On the propagation of Jovian electrons in the heliosphere: Transport modelling in 4-D phase space
Fichtner, Horst; Potgieter, Marius; Ferreira, Stefan +1 more
For about 25 years the Jovian magnetosphere is known to be a strong source of electrons with energies up to ∼30 MeV. Many in-situ observations have not only confirmed this finding originally made with the Pioneer 10 spacecraft, but have also revealed that the Jovian electrons appear to be present, at least close to the ecliptic plane, in the dista…