Search Publications
Properties of coronal mass ejections: SOHO LASCO observations from January 1996 to June 1998
St. Cyr, O. C.; Plunkett, S. P.; Michels, D. J. +9 more
We report the properties of all the 841 coronal mass ejections (CMEs) observed by the Solar and Heliospheric Observatory (SOHO) Large Angle Spectroscopic Coronagraph (LASCO) C2 and C3 white-light coronagraphs from January 1996 through June 1998, and we compare those properties to previous observations by other similar instruments. Both the CME rat…
Relationship of halo coronal mass ejections, magnetic clouds, and magnetic storms
Thompson, B. J.; Webb, D. F.; Crooker, N. U. +2 more
Halo coronal mass ejections (CMEs) had been rarely reported in coronagraph observations of the Sun before the Solar and Heliospheric Observatory (SOHO) mission. Since mid-1996, however, the SOHO Large Angle Spectrometric Coronagraph (LASCO) instruments have observed many halo or partial-halo CMEs. A halo CME, especially when associated with solar …
The origin and development of the May 1997 magnetic cloud
Plunkett, S. P.; Webb, D. F.; Burlaga, L. F. +5 more
A complete halo coronal mass ejection (CME) was observed by the SOHO Large-Angle and Spectrometric Coronagraph (LASCO) coronagraphs on May 12, 1997. It was associated with activity near Sun center, implying that it was aimed earthward. Three days later on May 15 an interplanetary shock and magnetic cloud/flux rope transient was detected at the Win…
Detection of coronal mass ejection associated shock waves in the outer corona
Sheeley, N. R.; Hakala, W. N.; Wang, Y. -M.
White light coronal images from the Large-Angle Spectrometric Coronagraph (LASCO) on the Solar and Heliospheric Observatory (SOHO) spacecraft show disturbances propagating away from high-speed coronal mass ejections (CMEs). The disturbances are faintly visible ahead of the ejected material at the noses of the CMEs but are strongly visible along th…
A four-fluid turbulence-driven solar wind model for preferential acceleration and heating of heavy ions
Habbal, Shadia R.; Esser, Ruth; Hu, You Qiu
We present for the first time a one-dimensional, four-fluid turbulence-driven solar wind model in order to investigate the preferential acceleration and heating of heavy ions by the resonant cyclotron interaction with parallel-propagating left-hand-polarized ion cyclotron waves. The model contains four species: electrons, protons, alpha particles,…
Cyclotron resonance in coronal holes: 3. A five-beam turbulence-driven model
Hollweg, Joseph V.
Following Hollweg and Johnson [1988], Isenberg [1990], and Li et al. [1999a], we postulate that the Sun launches a flux of low-frequency Alfvén waves, which dissipate via a turbulent cascade to high frequencies where the energy is absorbed by ion cyclotron resonant interactions. The plasma consists of two proton beams, which are proxies for the re…
Charge state distributions of iron in impulsive solar flares: Importance of stripping effects
Ruffolo, D.; Kocharov, L.; Kartavykh, Y. Y. +2 more
A model of stochastic acceleration of heavy ions by Alfvén wave turbulence has been developed. It takes into account spatial diffusion, Coulomb losses, and the possibility of charge changes for ions during stochastic acceleration. The main processes influencing the ionic charge states are the stripping by thermal electrons and protons as constitue…
Compressibility of ion cyclotron and whistler waves: Can radio measurements detect high-frequency waves of solar origin in the corona?
Hollweg, Joseph V.
The ultraviolet coronagraph spectrometer on Solar and Heliospheric Observatory (SOHO) has provided several lines of evidence strongly suggesting that coronal holes and the high-speed solar wind are heated by resonant interactions with ion cyclotron waves. Related evidence has also been provided by the solar ultraviolet measurements of emitted radi…
Latitudinal dependence of outflow velocities from O VI Doppler dimming observations during the Whole Sun Month
Kohl, John L.; Noci, Giancarlo; Gibson, Sarah E. +4 more
Empirical determinations of outflow velocities in the solar corona provide a much needed constraint, along with density and temperature determinations, of the acceleration and heating mechanisms in the extended corona. Much progress has been made on density determinations from white light polarized brightness observations but outflow velocities ha…
Model for the mass fractionation in the January 6, 1997, coronal mass ejection
Bochsler, Peter; Wurz, Peter; Lee, Martin A.
For the coronal mass ejection (CME) of January 6, 1997, strong element fractionation of the heavy ions was observed at 1 AU with the Mass Time-of-Flight (MTOF) sensor of the Charge, Element, and Isotope Analysis System (CELIAS) on the Solar and Heliospheric Observatory (SOHO). During the passage of the CME plasma and the passage of the erupted fil…