Heliophysics Science Division
Sciences and Exploration Directorate - NASA's Goddard Space Flight Center

August 26, 2011, 12:00 pm - 1:00 pm

August 26, 2011, 12:00 pm - 1:00 pm

Heliospheric Imagers: Who They? What Do? And Why?



Dr. Tim Howard,, Southwest Research Institute, Boulder

Coronal mass ejections and other solar wind transients have been observed by visible white light cameras since the first space-borne coronagraphs appeared 40 years ago. For much of that time they were also detected in-situ by a variety of spacecraft occupying many orbits. This left an 80 million mile gap between the solar corona and those in-situ spacecraft near the Earth. The last decade has seen the emergence of a new class of white light instrument. The heliospheric imager operates like a wide-field coronagraph, except that it is much more sensitive and observe a much larger intensity range. First with SMEI (2003) and then the HIs (2006), they have demonstrated their ability to regularly detect and track solar wind transients across the sky continuously from the Earth to the Sun, and beyond. Furthermore the geometry and physics that allow us to observe them change in ways that enable the extraction of 3-D properties directly from the heliospheric imager data alone. They have enabled the development of previously inaccessible science about the evolution of solar wind transients and improved our ability to predict both their time of arrival and likelihood of impact with the Earth. In this talk I will discuss the history of interplanetary transient detection, the status quo regarding heliospheric imagers, and plans for their future development.