Physics Colloquium, "Observations and Discoveries of Our Heliosphere’s Interstellar Interaction"

Presented by: D.J. McComas, Princeton University

Abstract: The solar wind and its embedded magnetic field flow outward from the sun in all directions, inflating a bubble in the local interstellar medium called the heliosphere. Prior to 2004, there were very few direct observations of the interaction of the heliosphere and local interstellar medium and our knowledge of these regions was largely theoretical. Then, 2004 and 2007 the Voyager 1 and 2 spacecraft crossed the heliosphere’s termination shock and in 2012 and 2018, each went on to cross the heliopause and entered interstellar space. IBEX – the Interstellar Boundary Explorer – launched in 2008, and has been returning 3-D global observations of ion distributions in the heliosheath and beyond via charge exchange Energetic Neutral Atoms (ENAs), continuously since then. These sets of observations are highly complementary with the Voyagers providing detailed in situ measurements along their two trajectories and IBEX returning all-sky maps of ENAs with energies from <0.1 to ~6 keV. Over the past decade and a half, these observations have led to numerous discoveries and “firsts” and a true scientific revolution in our understanding of the outer heliosphere and its interstellar interaction. With the continuation of the Voyagers and IBEX, and NASA’s recent selection of the Interstellar Mapping and Acceleration Probe (IMAP) to launch in 2024, the heliophysics community can look forward to many more years of outstanding new observations and innovative science. This seminar is adapted from the Parker Lecture recently presented at the 2018 Fall AGU meeting, includes connections to planned contributions to IMAP from CU/LASP, summarizes some of the biggest discoveries and most intriguing mysteries of the fascinating region that surrounds our Sun and forms our home in the galaxy.

Coffee, tea, and cookies will be available starting at 3:45 p.m., in DUAN G1B31.

Wednesday, January 23 at 4:00pm to 5:00pm


Duane Physics and Astrophysics, G1B20
2000 Colorado Avenue, Boulder, CO 80309

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