A discovery by NASA’s Parker Solar Probe (PSP), led by scientists at Southwest Research Institute (SwRI), has provided us with the first evidence of magnetic reconnection in the Sun’s upper atmosphere
The discovery confirms theoretical models that have guided solar science for nearly 70 years and could significantly improve the ability to predict space weather events that impact Earth.
Understanding the mechanics of solar explosions
Magnetic reconnection is a physical process that occurs in plasma, where magnetic field lines are broken and reconfigured, releasing intense amounts of energy. On the Sun, this phenomenon is responsible for explosive events such as solar flares and coronal mass ejections (CMEs), which can eject charged particles into space and interfere with Earth’s satellites, communication networks, and even power grids.
While reconnection has been observed near Earth previously due to missions like NASA’s Magnetospheric Multiscale (MMS), capturing direct evidence in the solar corona has remained rare. The Parker Solar Probe’s close approach to the Sun has finally enabled researchers to study this process where it originates.
Solar activity
On September 6, 2022, the Parker Solar Probe made a record-breaking approach to the Sun, entering regions of the corona never before explored by a spacecraft.
During this encounter, PSP flew through a massive solar eruption, collecting crucial data on plasma and magnetic fields. The data confirmed that the spacecraft had passed directly through a magnetic reconnection site within the Sun’s upper atmosphere.
This is the first time scientists have been able to sample and observe a reconnection event in the solar corona from such proximity. The findings were supported by concurrent observations from the European Space Agency’s Solar Orbiter, allowing a comprehensive analysis of the event.
Validating long-standing theories
The data collected during the PSP’s 2022 flyby matched predictions made by numerical models of magnetic reconnection that have existed since the mid-20th century. Previously, these models could only be partially tested using remote observations or simulations. The new findings confirm these models with real, high-resolution in-situ measurements.These observations close a gap in understanding how reconnection operates across different environments, from Earth’s magnetosphere to the turbulent, high-energy regions of the Sun. The research also shows how energy is transferred and how particles are accelerated during these explosive events.
Connecting scales and predicting space weather
The research team, led by SwRI, will now investigate whether turbulence, magnetic fluctuations, or wave activity also accompany reconnection in the regions identified by PSP. This further clarifies how energy builds up and is suddenly released in the solar atmosphere.
Understanding the whole mechanism behind magnetic reconnection on the Sun could help scientists create more accurate models for predicting solar storms and their effects on Earth. With space weather becoming increasingly relevant to modern technology, these new findings will have practical applications for protecting satellites, astronauts, and infrastructure on the ground.
The Parker Solar Probe, launched in 2018 as part of NASA’s Living with a Star program, was designed specifically to investigate solar phenomena that influence the Sun-Earth system. Managed by NASA’s Goddard Space Flight Centre and operated by the Johns Hopkins Applied Physics Laboratory, the spacecraft continues to make new contributions to heliophysics.
