Semiempirical Two‐dimensional MagnetoHydrodynamic Model of the Solar Corona and Interplanetary Medium

1999 ◽  
Vol 523 (2) ◽  
pp. 812-826 ◽  
Author(s):  
Edward C. Sittler, Jr. ◽  
Madhulika Guhathakurta
Keyword(s):  
Solar Corona ◽  
Interplanetary Medium ◽  
Two Dimensional ◽  
Magnetohydrodynamic Model

scholarly journals A numerical study of the interaction between two ejecta in the interplanetary medium: one- and two-dimensional hydrodynamic simulations

2004 ◽  
Vol 22 (10) ◽  
pp. 3741-3749 ◽  
Author(s):  
A. Gonzalez-Esparza ◽  
A. Santillán ◽  
J. Ferrer
Keyword(s):  
Hydrodynamic Model ◽  
Physical Mechanism ◽  
Interplanetary Medium ◽  
Numerical Study ◽  
Two Dimensions ◽  
Magnetic Clouds ◽  
The Sun ◽  
Two Dimensional ◽  
Hydrodynamic Simulations

Abstract. We studied the heliospheric evolution in one and two dimensions of the interaction between two ejecta-like disturbances beyond the critical point: a faster ejecta 2 overtaking a previously launched slower ejecta 1. The study is based on a hydrodynamic model using the ZEUS-3-D code. This model can be applied to those cases where the interaction occurs far away from the Sun and there is no merging (magnetic reconnection) between the two ejecta. The simulation shows that when the faster ejecta 2 overtakes ejecta 1 there is an interchange of momentum between the two ejecta, where the leading ejecta 1 accelerates and the tracking ejecta 2 decelerates. Both ejecta tend to arrive at 1AU having similar speeds, but with the front of ejecta 1 propagating faster than the front of ejecta 2. The momentum is transferred from ejecta 2 to ejecta 1 when the shock initially driven by ejecta 2 passes through ejecta 1. Eventually the two shock waves driven by the two ejecta merge together into a single stronger shock. The 2-D simulation shows that the evolution of the interaction can be very complex and there are very different signatures of the same event at different viewing angles; however, the transferring of momentum between the two ejecta follows the same physical mechanism described above. These results are in qualitative agreement with in-situ plasma observations of "multiple magnetic clouds" detected at 1AU.

Two-dimensional magnetohydrodynamic model of emerging magnetic flux in the solar atmosphere

1989 ◽  
Vol 345 ◽  
pp. 584 ◽  
Author(s):  
K. Shibata ◽  
T. Tajima ◽  
R. S. Steinolfson ◽  
R. Matsumoto
Keyword(s):  
Magnetic Flux ◽  
Solar Atmosphere ◽  
Two Dimensional ◽  
Magnetohydrodynamic Model

Coronal Broadening of the Crab Nebula 1969-71: Observations

1972 ◽  
Vol 2 (2) ◽  
pp. 84-86 ◽  
Author(s):  
R. G. Blesing ◽  
P. A. Dennison
Keyword(s):  
Solar Cycle ◽  
Solar Corona ◽  
Crab Nebula ◽  
Two Dimensional ◽  
Dimensional Image ◽  
Two Dimensional Image ◽  
The Crab Nebula

A description was given in a previous paper of the first observations of the two-dimensional image of the Crab Nebula as it became broadened by the solar corona in June 1969. In this paper we describe further observations at 80 MHz during 1970 and 1971, again using the CSIRO Radioheliograph at Culgoora, N.S.W., and we discuss the derived values for radial and tangential broadening in relation to previous work at various phases of the solar cycle. Other methods of observing angular broadening have generally employed two or three interferometers at different position angles, and only the simplest model for the image could be assumed in interpreting the results. The radioheliograph, however, has the advantage of recording the complete two-dimensional image and also, simultaneously, the surrounding background.

Some Investigations of the Solar Corona: The First Two Years of Observation With the Culgoora Radioheliograph

1970 ◽  
Vol 1 (8) ◽  
pp. 365-370 ◽  
Author(s):  
J. P. Wild
Keyword(s):  
Solar Corona ◽  
Interplanetary Medium ◽  
Present Writer ◽  
Present Review ◽  
Radio Sources ◽  
The Sun ◽  
Joint Effort ◽  
University Of Colorado ◽  
The University

The first meaningful observation with the 80 MHz Cul-goora radioheliograph was made on 2 September 1967, a few weeks before the instrument was officially commissioned. Systematic observations, normally for 4 to 6 hours per day, began late in February 1968 and the Sun has since been observed on 438 days. The remaining days and many nights have been used for investigations of radio sources and the interplanetary medium and for maintenance and instrumental extension. The standard of reliability thus achieved has been due to the sustained efforts of K. V. Sheridan, W. J. Payten, K. R. McAlister, M. Beard and their colleagues. These first two years have been a period mainly of exploration—a phase of great interest to those engaged in observing, though possibly bewildering to those not. The present review is a first attempt to collate and summarize what has so far been found and where possible to draw preliminary conclusions. The observations to be described and their discussion have been due to a joint effort on the part of a number of workers, particularly G. A. Dulk (on leave from the University of Colorado), K. Kai (on leave from the University of Tokyo), N. R. Labrum, D. J. McLean, A. C. Riddle, K. V. Sheridan, S. F. Smerd, R. T. Stewart, and the present writer. The period has also seen considerable development in the evolution of intricate computer programmes for analysing the data, particularly on the part of L. H. Heisler and D. J. McLean.

Space Weather

2015 ◽  
Author(s):  
Joanna D. Haigh ◽  
Peter Cargill
Keyword(s):  
Solar Wind ◽  
Solar Corona ◽  
Space Weather ◽  
Coronal Mass Ejections ◽  
Interplanetary Medium ◽  
Earth Satellite ◽  
Satellite Observations ◽  
Space Environment ◽  
The Sun ◽  
The Earth

This chapter focuses on the link between Sun and Earth generically known as space weather. This link is referred to as the occurrence in the solar corona of energetic phenomenon such as flares and coronal mass ejections which can have a major impact on the Earth's space environment. There were other discoveries in subsequent years, but the 1950s and 1960s brought major advances in the understanding of the connection between the Sun and the Earth. Satellite observations confirmed the existence of the solar wind, so that the nature of the interplanetary medium was identified and measured. Such continuous monitoring of the Sun and solar wind has, in turn, led to methods for predicting deleterious space weather.

Corotation and Solar Wind in the Solar Corona and Interplanetary Medium

1967 ◽  
Vol 147 ◽  
pp. 220 ◽  
Author(s):  
V. C. A. Ferraro ◽  
V. B. Bhatia
Keyword(s):  
Solar Wind ◽  
Solar Corona ◽  
Interplanetary Medium
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