PUNCH News

Energetic particles associated with shocks driven by fast coronal mass ejections (CMEs) or shocks developed by stream interaction regions (SIRs) often extend to high energies and are key elements of space weather. PUNCH is designed to track of solar wind structures through interplanetary space. Dayeh et al. (2025) reported a strong and robust relation between the shock speed jump magnitude at CME and SIR shocks, and the peak fluxes of energetic particles. Their analysis was based on 59 CME-driven shocks and 74 CIRs observed by Wind/STEP between 1997 – 2023. With that relationship, QuickPUNCH image sequences, and new methods for identifying speed jumps in the solar wind, we can forecast shock-associated particle events and their location in interplanetary space. PUNCH science data may become a crucial input to forecasting radiation events in the inner heliosphere.

The AIAA Small Satellite conference nominated PUNCH as a finalist for its prestigious Smallsat Mission of the Year award!

Scale-invariant 1/ƒ noise is a familiar observation across a wide array of natural and artificial systems, including heart rate fluctuations and loudness patterns in musical compositions. In the solar wind, it is seen mostly in the magnetic field energy spectrum across timescales from minutes to several days, where it represents fluctuations with equal power per frequency octave. First identified in the heliosphere in the 1980s, 1/ƒ noise has prompted ongoing discussion concerning its generation mechanism and place of origin – whether it forms locally in the solar wind or, as suggested by the long timescale of its influence, it stems from deeper solar processes linked to coronal dynamics and the solar dynamo. NASA’s PUNCH mission will capture high-resolution images of the inner solar wind and the corona, allowing studies of the spatial structures of the plasma that may be associated with the 1/ƒ observations1, with the potential to reveal the origin and evolution of these enigmatic heliospheric 1/ƒ signals. In preparation for these new observations, PhD student Victoria Wang (working with PUNCH Co-Investigator William Matthaeus) and colleagues have reviewed the current state of our understanding of in the heliosphere as our third featured paper from the Solar Physics PUNCH Mission Overview Topical Issue (J. Wang et al., Solar Physics, 2024, 299:169).

Come Play in the PUNCH Sandbox! Get to know PUNCH data and have your questions answered by the experts.

The solar wind is turbulent. One of PUNCH’s major objectives is to study that turbulent flow. However, obtaining quantitative information about in-situ processes from our images can be challenging. PUNCH images integrate all light along the line of sight between the observer and infinity, so the structure of local turbulence is blurred. We therefore expect its measurements to relate differently from previous in-situ data to the underlying turbulent environment of the outer corona and inner heliosphere. To understand these differences, we mimic the action of PUNCH observation itself (using the FORWARD tool, Gibson+2016), processing “ground truth” magnetohydrodynamic simulations of turbulence to obtain synthetic white-light (PUNCH-like) images. Direct 1-to-1 comparison of the simulation to “PUNCHified” images of the same shows how PUNCH observations change the spatial spectrum of the turbulence. By simple integration (projection) of the simulated densities from 3D to 2D, we can match the PUNCH-specific variation from the more sophisticated FORWARD model images. Compiling a catalog of simulations with different properties that match PUNCH remote observations will be the key to determining the properties of the solar wind simultaneously across the vast PUNCH field of view, yielding coverage impossible to attain with in-situ spacecraft alone. In preparation for these new observations, Associate Investigator Francesco Pecora and colleagues have undertaken the forward analysis described above as Paper 2 of the Solar Physics PUNCH Mission Overview Topical Issue, providing context and guidance for PUNCH as it obtains its brand new view on solar wind turbulence.

PUNCH is about to get a close look at a “point-of-no-return” zone surrounding the Sun. Charged particles fly away from the Sun in the form of the steady solar wind and bursty coronal mass ejections (CMEs), and most of those particles escape all the way out past the planets of our solar system. Sometimes, though, particles fall back down, but only if they're below the Sun's Alfvén surface --- named after Nobel-Prize-winning physicist Hannes Alfvén. This surface has been theorized since the 1960s, but has only been explored directly since 2021, when NASA's Parker Solar Probe plunged through it for the first time.

PUNCH tracks space weather and the solar wind itself across the entire inner solar system. This preliminary movie marks the first time a complete halo CME has been tracked all the way across the inner solar system, to impact with Earth.