Parker Solar Probe Witnesses Unprecedented Sunward Plasma Jet Driven by Magnetic Reconnection

NASA's Parker Solar Probe recorded an unprecedented plasma explosion in the Sun's corona, with a jet of particles blasting toward the star's surface. This rare event produced a sunward jet of plasma and accelerated protons to about 1,000 times the expected energy. Parker's unique vantage point between the event and the Sun let scientists trace the jet back to a magnetic reconnection site. In such events, twisted solar magnetic field lines snap and realign, explosively converting stored magnetic energy into fast-moving plasma. These direct observations shed new light on how magnetic reconnection powers the solar wind and may improve space weather forecasts.

Sunward Plasma Jet and Magnetic Reconnection

The new reconnection findings were reported in a May 2025 Astrophysical Journal Letters paper, as Parker crossed the Sun's heliospheric current sheet (an undulating boundary where the solar magnetic field flips), it flew directly through the exhaust of a reconnection event. Over a four-hour span in late 2022, the probe measured a sunward-pointing plasma jet and trapped protons energized to nearly 1,000 times what the local magnetic field could supply. These measurements unambiguously tied the particles' origin to magnetic reconnection.

Magnetic reconnection is the process in which magnetic field lines break and reconnect, converting magnetic energy into motional energy of charged particles in various natural and controlled environments, including terrestrial and planetary magnetospheres, solar and stellar flares, and fusion devices.

Implications for Space Weather and Future Research

Understanding these processes is crucial for space weather forecasting. Intense solar activity and the steady solar wind can strip planetary atmospheres (as happened to Mars) and trigger geomagnetic storms at Earth. Such storms can blackout power grids, damage satellites, and disrupt GPS and radio communications.

For example, May 2024 solar storms disrupted GPS-guided farming equipment, causing an estimated $500 million in losses. Because the Sun's magnetic field is so vast and tangled, computer models must simplify it; Parker's in-situ measurements help refine these models.