SECCHI team obtains images of the solar wind at Earth

December 07, 2007

Using 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.
The STEREO/SECCHI data used in this research were produced by an international consortium including NRL, Lockheed Martin Solar and Astrophysics Lab, NASA Goddard Space Flight Center, Rutherford Appleton Laboratory, University of Birmingham, Max-Planck-Institut fur Sonnensystemforschung, Centre Spatiale de Liege, Institut d'Optique Thorique et Applique, and Institut d'Astrophysique Spatiale.

Dr. Sheeley's talk, titled "Secchi Observations of Mass Flows in the Inner Heliosphere will take place on Thursday December 13, beginning at 10:20 in Room 307 of Moscone South.

Naval Research Laboratory

Related Spacecraft Articles from Brightsurf:

Final images from Cassini spacecraft
Researchers are busy analysing some of the final data sent back from the Cassini spacecraft which has been in orbit around Saturn for more than 13 years until the end of its mission in September 2017.

New nano-barrier for composites could strengthen spacecraft payloads
The University of Surrey has developed a robust multi-layed nano-barrier for ultra-lightweight and stable carbon fibre reinforced polymers (CFRPs) that could be used to build high precision instrument structures for future space missions.

'Oumuamua is not an alien spacecraft
Early reports of the interstellar visitor 'Oumuamua's odd characteristics led some to speculate that the object could be an alien spacecraft, sent from a distant civilization to examine our star system.

NASA's TESS spacecraft starts science operations
NASA's Transiting Exoplanet Survey Satellite has started its search for planets around nearby stars, officially beginning science operations on July 25, 2018.

NASA spacecraft finds new type of magnetic explosion
Four NASA spacecraft have observed magnetic reconnection in a turbulent region of the Earth's outer atmosphere known as the magnetosheath, the planet's first line of defense against the intensity of the solar wind.

do spacecraft, newborns and endangered shellfish have in common?
Researchers at University of California San Diego School of Medicine have developed a microbial detection technique so sensitive that it allows them to detect as few as 50-100 bacterial cells present on a surface.

Promising sensors for submarines, mines and spacecraft
Researchers from the Physics Department of Moscow State University and their colleagues have discovered a mechanism that allows gas sensors, based on nanocrystalline metal oxides, to work at room temperature.

NASA'S OSIRIS-REx spacecraft slingshots past Earth
NASA's asteroid sample return spacecraft successfully used Earth's gravity on Friday to slingshot itself on a path toward the asteroid Bennu, for a rendezvous next August.

On the road to creating an electrodeless spacecraft propulsion engine
Experiments by researchers give clues about the behavior of plasma in different environments.

NASA spacecraft investigate clues in radiation belts
NASA's Van Allen Probes uncover new phenomena in our near-Earth environment with their unique double orbit.

Read More: Spacecraft News and Spacecraft Current Events is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to