Imaging The Solar Wind At 1 AU. With Stereo/hi-2
Abstract
The STEREO/HI-2 wide-field imagers have demonstrated the importance of heliospheric imaging to understanding CMEs and the solar wind, but the difficulty of background subtraction has precluded full exploitation of this rich resource: current results are based mainly on morphological studies of running difference movies and time-elongation "J-plots". With a combination of several commonly used image processing techniques, we have developed a pipeline to extract quantitative wind imagery from HI-2 at elongation angles as high as 70 degrees from the Sun and brightness ranges 3-4 orders of magnitude fainter than the background.
The processed data reveal to direct view a surprising menagerie of features in the solar wind: voids within CMEs, remnant loop structures, disconnected plasmoids, current sheets, interacting streams, and compressive wave fronts. Despite motion blur of 1-3 degrees in the HI-2 instrument, in some cases the images are clear enough to reveal striated "tracer” structures that appear to follow the magnetic field, just as in the solar corona. We will briefly summarize the reduction pipeline, demonstrate its output with spectacular movies of Earth-directed events and "quiet Sun", and present preliminary results from examination of the quantitative data. This work was supported in major part by NASA's SHP-GI program.- Publication:
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AAS/Solar Physics Division Abstracts #42
- Pub Date:
- May 2011
- Bibcode:
- 2011SPD....42.1402D