Advancing The Polar Perspective Of The Sun


An artist's depiction of a solar-sail powered spacecraft like that needed to investigate the Sun's high latitude evolution.

Ask almost anyone in the solar physics community, "What observational viewpoint would yield the biggest scientific breakthroughs in the shortest time?" Almost unequivocally, the response would be either a mission to fly, or “hover,” over the Sun’s poles. Technology is advancing at such a pace—the miniaturization of once complex and massive instruments, and the propulsion concepts to access non-Keplerian orbits like solar sails—that such missions are feasible at present budget levels. In an effort to raise the scientific profile of such missions and to gather scientific input on what the highest priority observations and science goals for such a mission may be, HAO organized the “Polar Perspectives 2018” workshop.

Motivated, in large part, by the combined data of the SOHO, STEREO, and SDO spacecraft, we were able, from 2011 to 2014, to image the entire Sun for the first time in human history. Those observations have demonstrated some of the rotationally driven processes of our Star that we have missed or overlooked. They presented a tantalizing glimpse of the Sun’s polar evolution when the observations are pieced together, despite the fact that all of these spacecraft are observing the poles from close to the ecliptic plane. For decades, observations of high solar latitudes have been used as critical precursor input for predictions of decadal-scale solar activity. Many solar high-latitude phenomena—including polar coronal holes, polar crown filaments, and the Sun’s torsional oscillations—indicate a limiting latitude around 55 degrees that apparently divides high- vs. low-latitude dynamical evolution. The lack of measurements from high solar latitude vantage points has presented a significant hurdle to understanding.

More than 75 attendees from around the world came to HAO’s Center Green campus to participate in three days of presentations, discussions, and breakouts, constructing conceptual mission payloads, orbits, and objectives. Others followed the diverse set of discussions as they were webcast and submitted their input to the discussions. A polar view of the Sun would directly reveal the Sun’s global-scale dynamics, investigate the sources of the fast solar wind, and witness the full lifetime of structures in the solar atmosphere from birth to death, including a Sun-to-Earth view of coronal mass ejections—dramatically reducing the uncertainties in forecasting the impacts of solar storms on our planet. Outcomes of the meeting will be presented in peer-reviewed journal articles and white papers that will be submitted to the upcoming Astronomy/Astrophysics and Solar/Space Physics Decadal Surveys as the community begins to decide which of the biggest scientific challenges to concentrate on.

The recorded presentations and other materials from Polar Perspectives 2018 can be found here.