Search Publications
Remote infrared observations of parent volatiles in comets: A window on the early solar system
Dello Russo, N.; Mumma, M. J.; DiSanti, M. A. +3 more
Organic volatiles and water in Oort Cloud comets were investigated at infrared wavelengths. The detected species include H 2O, CO, CH 3OH, CH 4, C 2H 2, C 2H 6, OCS, HCN, NH 3, and H 2CO. Several daughter fragments (CN, OH, NH 2, etc.) are…
Relation between the radial speed and theexpansion speed of coronal mass ejections
Schwenn, R.; Gonzalez, W. D.; Dal Lago, A.
We have selected 57 limb coronal mass ejections observed by LASCO during the period of January1997 to April 2001. We used the related EIT activity close to the limb to define these CMEs as "limbs". We measured the radial speed of the leading edge close to the center of these CMEs and the lateral expansion speed of the structures. Comparison of bot…
Discontinuity observations with cluster
Balogh, A.; Neubauer, F. M.; Horbury, T. +1 more
Observations of solar wind magnetic field discontinuities using four spacecraft allow their orientation to be estimated by relative timings referred to as triangulation. From February 1st until May 13th 2001 the Cluster orbit traversed the solar wind. During these periods we identified 489 directional discontinuities (DDs) using the Tsurutani-Smit…
Coronal mass ejections: Initiation and detection
Gopalswamy, N.
Coronal mass ejections (CMEs) are large-scale magnetic structures expelled from the Sun due to MHD processes involving interaction between plasma and magnetic field in closed field regions. I provide a summary of the observational signatures and current models on CME initiation. I also discuss the multiwavelength signatures of CMEs, which have hel…
Properties of narrow coronal mass ejections observed with LASCO
Howard, R. A.; Gopalswamy, N.; Michalek, G. +1 more
We report the statistical properties of narrow coronal mass ejections (CMEs, angular width < 20°) withparticular emphasis on comparison with normal CMEs. We investigated 806 narrow CMEs from an online LASCO/CME catalog and found that (1) the fraction of narrow CMEs increases from 12% to 22% towards solar maximum, (2) during the solar maximum, t…
Solar maximum low-energy particle observations at heliographic latitudes above 75 degrees
Lario, D.; Reisenfeld, D. B.; Roelof, E. C. +1 more
We present a preliminary analysis of low-energy particle observations by the Ulysses and ACE spacecraft during the time intervals that Ulysses spent at heliographic latitudes above 75 degrees during its solar maximum orbit. The most southerly and northerly latitudes (80.2°) were reached by Ulysses in November 2000 and October 2001, respectively. T…
Soho observations relating to the association between flares and coronal mass ejections
Harrison, R. A.
Campaigns to investigate the solar coronal mass ejection (CME) onset have been run using the Solar andHeliospheric Observatory (SOHO) since 1996. These have included coronagraph and extreme-ultraviolet (EUV) disc imaging, along with magnetic mapping of the photosphere, in concert with EUV and UV spectroscopic observations. These campaigns have inc…
Particle drift effects on cosmic ray modulation during solar maximum
Ferreira, S. E. S.; Potgieter, M. S.; Heber, B.
A fully time-dependent cosmic ray modulation model based on the numerical solution of Parker's transport equation is used to study the amount of particle drifts needed to explain the observed 1.2 GV electron to Helium ratio at Earth and the 2.5 GV electron to proton ratio (e/p) observed by the KET instrument on the Ulysses spacecraft. The model su…
Energetic particle acceleration by coronal mass ejections
Kahler, S. W.
The current paradigm for the source of large, gradual solar energetic particle (SEP) events is that theyare accelerated in coronal/interplanetary shocks driven by coronal mass ejections (CMEs). Early studies established that there is a rough correlation between the logs of the CME speed and the logs of the SEP intensities. Here I review two topics…
Modulation of galactic cosmic rays at solar maximum: Observations
Zhang, Ming
The spectra of galactic cosmic rays observed anywhere inside the heliosphere are modulated by the sun because the charged particles must fight their ways inward against the radially expanding solar wind. In the past half a century, galactic cosmic ray fluxes at Earth were continuously monitored by neutron monitors on the ground and instruments on …