Search Publications
The correlation between solar energetic particle peak intensities and speeds of coronal mass ejections: Effects of ambient particle intensities and energy spectra
Kahler, S. W.
The correlation of peak intensities of solar energetic particle (SEP) events with the speeds of the associated coronal mass ejections (CMEs) is understood to be a result of SEP acceleration at shocks driven by the CMEs. However, the peak SEP intensities associated with CMEs of a given speed vary over ~ 4 orders of magnitude. We examine a database …
The heliospheric current sheet
Smith, Edward J.
The heliospheric current sheet (HCS) is the boundary between open oppositely directed magnetic field lines which commonly originate as the outward extension of the solar magnetic dipole. The dipole tilt, the rotation of the Sun, and the outward propagation of the solar wind cause peaks and valleys in the current sheet which spiral outward. The HCS…
Three-dimensional numerical simulation of MHD waves observed by the Extreme Ultraviolet Imaging Telescope
Plunkett, S. P.; Thompson, B. J.; Wu, S. T. +4 more
We investigate the global large amplitude waves propagating across the solar disk as observed by the SOHO/Extreme Ultraviolet Imaging Telescope (EIT). These waves appear to be similar to those observed in Hα in the chromosphere and which are known as ``Moreton waves,'' associated with large solar flares [Moreton, 1960, 1964]. Uchida [19…
Near-Sun and near-Earth manifestations of solar eruptions
Kaiser, M. L.; Gopalswamy, N.; Bougeret, J. -L. +1 more
We compare the near-Sun and near-Earth manifestations of solar eruptions that occurred during November 1994 to June 1998. We compared white-light coronal mass ejections, metric type II radio bursts, and extreme ultraviolet wave transients (near the Sun) with interplanetary (IP) signatures such as decameter-hectometric type II bursts, kilometric ty…
Fast ejecta during the ascending phase of solar cycle 23: ACE observations, 1998-1999
Webb, D. F.; Burlaga, L. F.; Zurbuchen, T. H. +3 more
We discuss fast ejecta observed at 1 AU during a period of increasing solar activity from February 5, 1998, to November 29, 1999. ``Fast ejecta'' are transient, noncorotating flows that move past the Earth during a day or more, with a maximum speed >600 km s-1. We identify two classes of fast ejecta at 1 AU: (1) magnetic clouds, whos…
Improvements to the HAF solar wind model for space weather predictions
Dryer, M.; Smith, Z.; Fry, C. D. +5 more
We have assembled and tested, in real time, a space weather modeling system that starts at the Sun and extends to the Earth through a set of coupled, modular components. We describe recent efforts to improve the Hakamada-Akasofu-Fry (HAF) solar wind model that is presently used in our geomagnetic storm prediction system. We also present some resul…
Modulation of Jovian and galactic electrons in the heliosphere: 1. Latitudinal transport of a few MeV electrons
Fichtner, H.; Ferreira, S. E. S.; Potgieter, M. S. +2 more
The heliospheric modulation of galactic and Jovian electrons is studied using a fully three-dimensional, steady state model based on Parker's transport equation including the Jovian source. The modulation of low-energy electrons is a handy tool to establish and to construct a suitable diffusion tensor to assure compatibility between model computat…
Helium energetics in the high-latitude solar wind: Ulysses observations
Reisenfeld, D. B.; McComas, D. J.; Steinberg, J. T. +4 more
We present a study of the interplanetary evolution of solar wind helium (alpha particle) energetics. The analysis of Ulysses observations of the fast high-latitude solar wind concentrates on the radial evolution of the alpha-proton differential streaming vαp, the alpha temperature, and the alpha temperature anisotropy. Ulysses observati…
Ionization state and magnetic topology of coronal mass ejections
Woch, J.; Schwenn, R.; Balogh, A. +5 more
Charge state distributions of heavy solar wind ions measured in interplanetary space can be used to probe the physical conditions in the solar corona. This paper presents a study of the charge state distributions and the magnetic topology of 56 coronal mass ejections (CMEs) observed in interplanetary space by the Ulysses spacecraft. The analysis o…
Ion distributions in large magnetic holes in the fast solar wind
Smith, E. J.; Goldstein, B. E.; Neugebauer, M. +3 more
Magnetic holes are isolated localized depressions in the magnitude of the interplanetary magnetic field. Six examples of long-duration (9 to 30 min) magnetic holes observed by the Ulysses spacecraft at high heliographic latitudes near 3 AU are studied in detail. Each of the holes was in pressure balance with its surroundings. The proton-proton and…