Imaging Nearly Nothing At All, with PUNCH

Speaker: Craig DeForest (Southwest Research Institute) In Person and zoom

Zoom Recording Passcode: jMJ!rw4s

The Polarimeter to UNify the Corona and Heliosphere (PUNCH) is a NASA Small Explorer mission scheduled for launch in early 2025, comprising four smallsats to be launched into a Sun-synchronous 6am/6pm orbit in early 2025.  The spacecraft each host a single imaging instrument and work together to act as a “virtual coronagraph” with a 90° wide field of view centered on the Sun.  PUNCH science is focused on understanding the corona and the solar wind as a single, unified system, imaging the outer solar corona, “Alfvén zone” of transition to the solar wind, and the solar wind itself, in three dimensions with four minute cadence for the duration of the mission. PUNCH uses polarimetry to extract 3-D information about plasma structures in the solar wind.  In the outer reaches of the integrated field of view, the signal is less than 0.1% of the background — requiring careful calibration and image processing to extract the faint sunlight Thomson-scattered by the solar wind itself.  The next science meeting, PUNCH 6 “Ready for Launch”, is open to all and will be held at Cal Poly San Luis Obispo on February 25-26 of 2025.  In this seminar I will describe the mission science, the status of the mission itself, and some of the technical challenges that had to be overcome to produce PUNCH data — in the mission design, in the instruments, and in the data-reduction pipeline.