PUNCH News & Nuggets

We invite the community to attend the seventh PUNCH (Polarimeter to UNify the Corona and Heliosphere) Science Meeting from May 12th through the 14th, 2026 in Boulder, Colorado. As of May 2025, PUNCH has been taking observations, and everyone is invited to share their early results from these data. Topical science sessions will be organized around the themes of the origin and evolution of the ambient solar wind and turbulence within it and the physics, tracking, and predictability of transient events including CMEs, CIRs, and shocks.

Parker Solar Probe (PSP) orbits the Sun three times per year in a highly elliptical orbit, passing through the corona itself at perihelion. PUNCH stays at Earth, surveying the entire inner solar system. PSP is always within the PUNCH field-of-view, allowing joint cross-scale studies of coronal and solar wind physics. This movie and still image, made by the PUNCH Science Operations Center’s Sam Van Kooten, highlight that relationship. The PUNCH intermediate-data-product movie (F corona removed; starfield intact) at left shows the Parker Solar Probe orbit. The overlain geometry shows the field of view of the WISPR instrument on board PSP. WISPR looks out from PSP through the imaged projection planes, producing the grayscale images at right (courtesy G. Stenborg, WISPR Consortium).

PUNCH Wide Field Images are now able to provide 3-D reconstructions of the inner heliosphere over time1. The PUNCH 90-degree view around the Sun from Earth captures images of the outward-moving heliospheric structures. For this analysis, these images have had the f-corona, stellar residuals, and stray light removed. Computerized tomography analysis converts these images into perspective views of outward-moving space weather systems.

Heliophysicists have produced the first continuous, two-dimensional maps of the Sun’s Alfvén surface – the region of space where the solar wind irrevocably escapes the grip of the Sun’s magnetic field – and demonstrated the dynamical variation of its properties as our star moves through its activity cycle. Beyond this boundary, the speed of outflowing solar material becomes faster than the speed of magnetic waves, marking an effective outer “edge” of the solar atmosphere. Published in The Astrophysical Journal Letters (Badman et al. 2025) and co-authored by PUNCH Co-I Rohit Chhiber, the study employed a combination of in-situ measurements and magnetic models from several space missions spanning a range of distances from the Sun, to infer the location of the Alfvén surface in the Sun’s equatorial plane, thereby providing a “top-down” view (looking downwards from above the solar system) of its probable shape. Tracking the surface’s evolution from 2018 (when the Sun was dormant) to 2025 (when it was highly active) revealed that its distance from the Sun, its thickness, and its “spikiness” increased with solar activity.

On 11-Mar-2025, PUNCH launched into Sun-synchronous polar orbit on a Falcon 9 spacecraft, in a rideshare with the SPHEREx mission. In the 365 days since then, PUNCH has downlinked ~1.5 million images from space, tracked over 100 CMEs, observed several new comets and one interstellar visitor, and changed the way humanity sees our environment in space. We are still refining the data processing for the most complex ground pipeline produced for any Explorer mission, but the images are already spectacular. Get ready for an amazing year of PUNCH science results ahead!

Polarization puts the "P" in PUNCH! The ratio of radially to tangentially polarized Thomson-scattered white light provides a powerful tool for locating the 3D position of compact structures in the solar corona and inner heliosphere, and PUNCH has been designed to take full advantage of this capability.

The Polarimeter to Unify the Corona and Heliosphere (PUNCH) is a complicated mission to do a very simple thing: image the entire outer corona and inner heliosphere, all the time, in 3D. This overview paper describes the entire design arc: the motivating science, the mission science requirements and their definition process, the mission design, the instrumentation, the data products and analysis tools, and at least some additional science enabled by PUNCH.