Search Publications
Trapping of Solar Energetic Particles by the Small-Scale Topology of Solar Wind Turbulence
Matthaeus, W. H.; Ruffolo, D.; Chuychai, P.
The transport of energetic particles perpendicular to the mean magnetic field in space plasmas has long been viewed as a diffusive process. However, there is an apparent conflict between recent observations of solar energetic particles (SEPs): (1) Impulsive solar flares can exhibit ``dropouts'' in which the SEP intensity near Earth repeatedly disa…
Discovery of GRB 020405 and Its Late Red Bump
Piro, L.; Mitrofanov, I.; Axelrod, T. S. +41 more
We present the discovery of GRB 020405 made with the Interplanetary Network (IPN). With a duration of 60 s, the burst appears to be a typical long-duration event. We observed the 75 arcmin2 IPN error region with the Mount Stromlo Observatory's 50 inch robotic telescope and discovered a transient source that subsequently decayed and was …
Perpendicular Transport of Solar Energetic Particles in Heliospheric Magnetic Fields
McKibben, R. B.; Zhang, Ming; Jokipii, J. R.
This paper presents direct observational evidence for large perpendicular diffusive flows of solar energetic particles in heliospheric magnetic fields. Using anisotropy measurements of 40-92 MeV protons obtained by the High-Energy Telescope of the COSPIN consortium on Ulysses at high heliographic latitudes, we find that during several gradual sola…
An Extended Burst Tail from SGR 1900+14 with a Thermal X-Ray Spectrum
Hurley, Kevin; Kouveliotou, Chryssa; Göǧüş, Ersin +6 more
The soft gamma repeater SGR 1900+14 entered a new phase of activity in 2001 April initiated by the intermediate flare recorded on April 18. Ten days following this flare, we discovered an abrupt increase in the source flux between consecutive Rossi X-Ray Timing Explorer (RXTE) orbits. This X-ray flux excess decayed over the next several minutes an…
Temporal Evolution of a Streamer Complex: Coronal and in Situ Plasma Parameters
Parenti, S.; Romoli, M.; Riley, P. +5 more
We report on observations acquired by the Ultraviolet Coronagraph Spectrometer (UVCS) aboard the Solar and Heliospheric Observatory (SOHO), from 2000 June 10 to June 17 at the time of a SOHO-Sun-Ulysses quadrature. UVCS took data at 1.6 and 1.9 Rsolar with a slit normal to the solar radius and centered along the radial to Ulysses. A str…
The 2001 April Burst Activation of SGR 1900+14: X-Ray Afterglow Emission
Hurley, K.; Costa, E.; Mereghetti, S. +8 more
After nearly two years of quiescence, the soft gamma-ray repeater SGR 1900+14 again became burst-active on 2001 April 18, when it emitted a large flare, preceded by few weak and soft short bursts. After having detected the X- and gamma-prompt emission of the flare, BeppoSAX pointed its narrow field X-ray telescopes to the source in less than 8 hr.…
Observations of Giant Outbursts from Cygnus X-1
Cline, T.; Hurley, K.; Golenetskii, S. +5 more
We present interplanetary network localization, spectral, and time history information for seven episodes of exceptionally intense gamma-ray emission from Cyg X-1. The outbursts occurred between 1995 and 2003, with durations up to ~28,000 s. The observed 15-300 keV peak fluxes and fluences reached 3×10-7 ergs cm-2 s-1
SOHO-Ulysses Spring 2000 Quadrature: Coronal Diagnostic Spectrometer and SUMER Results
Parenti, S.; Landi, E.; Bromage, B. J. I.
We present results from SOHO/CDS and SOHO/SUMER coordinated observations of coronal streamers made during the spring 2000 quadrature of SOHO, the Sun, and Ulysses. These observations form part of the JOP 112, which is primarily aimed at investigating the composition of the regions of the corona and the solar wind observed by both SOHO and Ulysses.…
Solar Wind Effects on the Transport of 3-10 MeV Cosmic-Ray Electrons from Solar Minimum to Solar Maximum
Fichtner, H.; Ferreira, S. E. S.; Potgieter, M. S. +2 more
We investigate the effects on the transport of a few MeV (~7 MeV) Jovian and Galactic electrons for different solar wind speed scenarios applicable to different heliospheric conditions. A three-dimensional, steady state model is used based on numerically solving Parker's transport equation, including the Jovian electron source, to compare model co…
The 2001 April Burst Activation of SGR 1900+14: Pulse Properties and Torque
Frontera, F.; Hurley, K.; Mereghetti, S. +10 more
We report on observations of SGR 1900+14 made with the Rossi X-Ray Timing Explorer (RXTE) and BeppoSAX during the 2001 April burst activation of the source. Using these data, we measure the spin-down torque on the star and confirm earlier findings that the torque and burst activity are not directly correlated. We compare the X-ray pulse profile to…