Search Publications
Charged-Particle Motion in Multidimensional Magnetic Field Turbulence
Giacalone, J.; Jokipii, J. R.
We present a new analysis of the fundamental physics of charged-particle motion in a turbulent magnetic field using a numerical simulation. The magnetic field fluctuations are taken to be static and to have a power spectrum which is Kolmogorov. The charged particles are treated as test particles. It is shown that when the field turbulence is indep…
The Coronal Electron Density Distribution Determined from Dual-Frequency Ranging Measurements during the 1991 Solar Conjunction of the ULYSSES Spacecraft
Bird, M. K.; Asmar, S. W.; Volland, H. +3 more
Dual-frequency ranging and Doppler measurements were conducted in support of the Ulysses Solar Corona Experiment (SCE) at and around the spacecraft's first solar conjunction in 1991 August. The differential group delay time between range codes on the two downlink carrier signals at the wavelengths 13.1 and 3.6 cm, a direct measure of the total ele…
Network Synthesis Localization of Two Soft Gamma Repeaters
Cline, T.; Kouveliotou, C.; Sommer, M. +5 more
We introduce the method of 'network synthesis,' which allows the detection of very weak gamma-ray transient signals in the data of the Ulysses gamma-ray burst (GRB) experiment from repeating sources. It consists of defining a grid of alpha, delta values, and for each BATSE detection of a burst from a soft gamma repeater, predicting the arrival tim…
A Search for the Radio Counterpart to the 1994 March 1 Gamma-Ray Burst
Cline, T.; Frail, D. A.; Kulkarni, S. R. +7 more
We report on the results of a search for the radio counterpart to the bright γ-ray burst of 1994 March 1. Using the Dominion Radio Astrophysical Observatory Synthesis Telescope sensitive, wide-field radio images at 1.4 GHz and 0.4 GHz were made of a region around GRB 940301. A total of 15 separate radio images were obtained at each frequency, samp…
Rapid Searches for Counterparts of GRB 930131
Schaefer, Bradley E.; Coe, M. J.; Ricker, George R. +39 more
A fading counterpart to a gamma-ray burst (GRB) would appear as a point source inside a GRB error region soon after the burst which dims on a timescale from minutes to days. The favorable circumstances of the burst GRB 930131 allowed for an international campaign to search for fading counterparts starting 6.8 hr after the burst. We report observat…
Directivity of 100--500 keV Solar Flare Hard X-Ray Emission
Hurley, K.; Niel, M.; Li, P. +3 more
We have identified 28 solar flares simultaneously observed by a SIGNE detector aboard the Venera 13 and Venera 14 spacecraft and the Hard X-Ray Burst Spectrometer (HXRBS) aboard the Solar Maximum Mission (SMM), over a wide range of observing angles. Fourteen of them were also observed by the Gamma Ray Spectrometer (GRS) on SMM and were included in…
Searching for Hard X-Ray Directivity during the Rise, Peak, and Decay Phases of Solar Flares
Li, Peng
We have identified 72 large solar flares (peak counting rates more than 1000 counts/s) observed by Hard X-ray Burst Spectroscopy (HXRBS) on-board the Solar Maximum Mission (SMM). Using a database of these flares, we have studied hard X-ray (50-850 keV) spectral center-to-limb variation and its evolution with time. The major results are the followi…
Diffusive Shock Acceleration in the Presence of Current Sheets
Jokipii, J. R.; Kota, J.
We study the nature of diffusive shock acceleration in the presence of current sheets which are oriented normal to the shock, so that the drift along the sheets carries particles either away from or toward the shock plane. We consider a system with periodic regions of alternating magnetic field direction. This can be taken to be a very crude repre…