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SECCHI team obtains images of the solar wind at Earth
December 10, 2007Using the Sun Earth Connection Coronal and Heliospheric Investigation (SECCHI) instruments on board NASA's Solar Terrestrial Relations Observatory (STEREO) spacecraft, a consortium of scientists has seen, for the first time, large waves of solar material sweeping past Earth.
The SECCHI team has obtained images of the density enhancements whose prior existence was known only from point measurements by in situ spacecraft. The team's results will be discussed during an invited talk by Dr. Neil Sheeley of the Naval Research Laboratory (NRL) at the fall meeting of the American Geophysical Union in San Francisco, CA, in December. The scientific paper is scheduled for publication in the March 1, 2008 issue of the Astrophysical Journal.
During relatively quiet solar conditions throughout the spring and summer of 2007, the SECCHI Heliospheric Imager HI-2 telescope on the STEREO B solar-orbiting spacecraft observed a succession of wavefronts sweeping past Earth. The scientists have compared these white-light images with in situ plasma and magnetic ?eld measurements obtained by near-Earth spacecraft, and found a perfect association between the occurrence of these waves and the arrival of high-density regions that rotate with the Sun. These compression regions are believed to form as high-speed wind from dark areas of the solar corona known as coronal holes run into the low-speed wind in front of it.
Currently, the researchers are tracking HI-2 waves backward toward the Sun to see exactly how they originate. Preliminary results suggest that the waves begin as blobs of material that are shed continuously from coronal streamers.
The STEREO twin spacecraft were launched on October 25, 2006 with the objective of obtaining stereoscopic observations of the Sun from a near-Earth orbit. After some initial maneuvers, which included a gravitational assist from the moon, the two spacecraft achieved their orbits with one spacecraft (A) located slightly closer to the Sun and gradually moving ahead of Earth and the other spacecraft (B) located slightly farther from the Sun and gradually falling behind. The angular distance between the A and B spacecraft increases at a rate of approximately 45 degrees per year and was about 26 degrees in early September 2007.
Each spacecraft is equipped with a suite of Sun Earth Connection Coronal and Heliospheric Investigation (SECCHI) instruments. In addition to an extreme ultraviolet imager (EUVI), there are two coronagraphs (COR1 and COR2) and two heliospheric imagers (HI-1 and HI-2) pointing 13 degrees and 53 degrees off to the side.
Naval Research Laboratory
Currently, the researchers are tracking HI-2 waves backward toward the Sun to see exactly how they originate. Preliminary results suggest that the waves begin as blobs of material that are shed continuously from coronal streamers.
The STEREO twin spacecraft were launched on October 25, 2006 with the objective of obtaining stereoscopic observations of the Sun from a near-Earth orbit. After some initial maneuvers, which included a gravitational assist from the moon, the two spacecraft achieved their orbits with one spacecraft (A) located slightly closer to the Sun and gradually moving ahead of Earth and the other spacecraft (B) located slightly farther from the Sun and gradually falling behind. The angular distance between the A and B spacecraft increases at a rate of approximately 45 degrees per year and was about 26 degrees in early September 2007.
Each spacecraft is equipped with a suite of Sun Earth Connection Coronal and Heliospheric Investigation (SECCHI) instruments. In addition to an extreme ultraviolet imager (EUVI), there are two coronagraphs (COR1 and COR2) and two heliospheric imagers (HI-1 and HI-2) pointing 13 degrees and 53 degrees off to the side.
Naval Research Laboratory
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Solar and Heliospheric Plasma Physics: Proceedings of the 8th European Meeting on Solar Physics, Held in Halkidiki, Near Thessaloniki, Greece, 13-18 May, 1996 (Lecture Notes in Physics) by G. M. Simnett (Author), C. E. Alissandrakis (Author), L. Vlahos (Author), Greece) European Meeting on Solar Physics 1996 (Chalkidike (Author), G. M. Simnett (Editor) This volume brings together theoretical ideas on the plasma physics of both hot and dense plasmas in the solar atmosphere and similar physics applied to the tenuous and cooler plasmas found in the heliosphere. It is complemented by recent observations. Helioseismology covers the solar interior and the neutrino problem. Solar and stellar activity cycles are addressed. The dynamics of magnetic flux tubes in the solar atmosphere and material flows through the chromosphere into the upper atmosphere are comprehensively reviewed. Energy release processes and the production of energetic particles are important to understanding events in the solar atmosphere and to the dynamics of the tenuous heliosphere. A glimpse of the future is offered by concluding chapters on new ground-based and space... |
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Solar Flare, Coronal and Heliospheric Dynamics (Advances in Space Research,) by E. Hiei (Author), J. L. Culhane (Author), Cospar (Author) | |
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Guidance and Control 1998 (Advances in the Astronautical Sciences) by Robert D. Culp (Editor), David Igli (Editor) | |
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The International Heliospheric Study by M. A. Shea (Author), E. J. Smith (Author), M.A. Shea (Author), E.J. Smith (Author) The International Heliospheric Study is a program sponsored by COSPAR that exploits the unique scientific opportunities presented by the continuing operation of the four Pioneer and Voyager spacecraft which are all in or beyond the outer solar system. The heliosphere is the region of space surrounding the sun which is dominated by the solar wind and from which the local interstellar plasma and magnetic field are excluded. The multispacecraft studies which form the basis of the IHS encompass the structure and dynamics of the solar wind and its interaction with the interstellar medium including those components, neutral gas and galactic cosmic rays, which are able to penetrate into the heliosphere. | |
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Solar and Heliospheric Origins of Space Weather Phenomena (Lecture Notes in Physics) by Jean-Pierre Rozelot (Editor) This book comprises an excursion through space weather, a scientific topic in rapid growth and with growing impact and complications for technological societies. The emphasis of the present volume is on the origins of space weather: the Sun and the solar mind. Very much as the Sun`s electromagnetic radiation drives the Earth climate, our space weather is driven by the solar wind. This book addresses students and scientists working, or interested in, the field and provides a thorough introduction to the topic for those who wish to become acquainted with the basic solar physics at the origin of space weather. |
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Solar cycle dynamics of solar, magnetospheric, and heliospheric particles, and long-term atmospheric coupling SAMPEX : progress report for grant NAG 5-2963; ... 1996 - July 1, 1997 (SuDoc NAS 1.26:204981) by G. M. Mason (Author) | |
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Magnetohydrodynamic (MHD) analyses of various forms of activity and their propogation through heliospheric space (SuDoc NAS 1.26:180176) by S. T. Wu (Author) | |
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The influence of the heliospheric current sheet and angular separation on flare accelerated solar wind (SuDoc NAS 1.26:175962) by Harald Martin Jakob Henning (Author) | |
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Potential flow downstream of the heliospheric terminal shock a non-spherical shock (SuDoc NAS 1.15:112145) by Steven Nerney (Author) | |
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Pioneer 10 and 11 heliospheric mission by Palmer Dyal (Author) |
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