Our Heliosphere and its Interstellar Interaction: A Solar Cycle of Global Observations and Discoveries

The supersonic solar wind and its embedded magnetic field continuously flow outward in all directions from the sun. This magnetized plasma inflates a bubble – the heliosphere – in the very-local interstellar medium (VLISM). The Interstellar Boundary Explorer (IBEX) mission launched in late 2008 and has been continuously returning 3-D global images of Energetic Neutral Atoms (ENAs) that derive from ion populations in the heliosheath and beyond. Now spanning more than a full solar cycle, IBEX’s all-sky maps and observations uniquely inform the global outer heliosphere and its evolving interstellar interaction. Insights from IBEX, in concert with in situ observations by the two Voyager spacecraft, which were transiting two different trajectories through the outer boundaries of the heliosphere contemporaneously with IBEX, have led to a true scientific revolution in our understanding of the outer heliosphere and its interstellar interaction. This Hannes Alfvén Medal Lecture will summarize some of the many discoveries and “firsts” from the IBEX mission and their implications for the outer heliosphere and VLISM. Finally, we will also look forward to the promise of the even more advanced Interstellar Mapping and Acceleration Probe (IMAP) mission, which is under development and slated to launch in 2025.