Search Publications
Relationship between CME Speed and Geomagnetic Storm Intensity
Venkatakrishnan, P.; Srivastava, Nandita
In this paper, we discuss the solar origin and interplanetary consequences of the coronal mass ejection of March 29, 2001 that was responsible for the most intense geomagnetic storm (DST ~ -377 nT) of the current solar cycle to date. A comparison of the CME of March 29, 2001, with a set of geo-effective halo CMEs associated with X-class…
Interplanetary radio emission due to interaction between two coronal mass ejections
Gopalswamy, Nat; Howard, Russell A.; Yashiro, Seiji +2 more
We report on the detection of a new class of nonthermal radio emission due to the interaction between two coronal mass ejections (CMEs). The radio emission was detected by the Radio and Plasma Wave Experiment (WAVES) on board the Wind satellite, while the CMEs were observed by the white-light coronagraphs of the Solar and Heliospheric Observatory …
Ionospheric and dayglow responses to the radiative phase of the Bastille Day flare
Mariska, J. T.; Warren, H. P.; Judge, D. L. +11 more
The Sun's Bastille Day flare on July 14, 2000 produced a variety of geoeffective events. This solar eruption consisted of an X-class flare followed by a coronal mass ejection that produced a major geomagnetic storm. We have undertaken a study of this event beginning with an analysis of the effects of the radiative phase of the flare on the dayglow…
Evaluation of solar Type II radio burst estimates of initial solar wind shock speed using a kinematic model of the solar wind on the April 2001 solar event swarm
Dryer, M.; Smith, Z.; Fry, C. D. +5 more
We compare simulation results of real time shock arrival time prediction with observations by the ACE satellite for a series of solar flares/coronal mass ejections which took place between 28 March and 18 April, 2001 on the basis of the Hakamada-Akasofu-Fry, version 2 (HAFv.2) model. It is found, via an ex post facto calculation, that the initial …
Fast acceleration of a CME-related X-ray structure in the low solar corona
Nitta, Nariaki V.; Alexander, David; Metcalf, Thomas R.
We report on a unique observation of the early and rapid acceleration of a fast CME in the low solar corona. The coronal disturbance associated with a LASCO CME and concurrent X1.2 flare on 1998 April 23 was well-observed by the Yohkoh Soft X-ray Telescope. The X-ray observations clearly show an accelerating structure, reaching 800-1100 km/s in ~5…
14-day forecast of solar indices using interplanetary Lyman α background data
Bertaux, Jean-Loup; Quémerais, Eric
We present a new method which can be used to forecast the variations of solar indices on the time scale of a half solar rotation. This method uses the Lyα interplanetary glow data obtained by the SWAN instrument on SOHO. We show how the maps of solar Lyα flux distributions derived from the SWAN data can be linked to the variation of activity on th…
A comparison of mean density and microscale density fluctuations in a CME at 10 Rsolar
Lynch, B. J.; Sheeley, N. R.; Coles, W. A.
We have observed intensity scintillation (IPS) of the radio source 0854 + 201 at 8 GHz on August 2, 2000 during the passage of a coronal mass ejection (CME) across the line of sight. The source was at a distance of 10 Rsolar over the north solar pole. Simultaneous observations with the LASCO C3 instrument allow us to model the mean dens…
The O+ and O++ emission lines near 834 Å in the quiet sun solar spectrum
Doschek, G. A.
I present quiet Sun solar disk averaged emission line intensities (at the Earth) and the full widths at half maximum intensity (FWHM) for the O+ and O++ emission lines that fall near 834 Å. These lines are important as excitation sources for O+ and O++ emission in the Earth's upper ionosphere, plasmasphe…