Energetic Particle Event
A sudden surge of high-energy particles (mainly protons) from the Sun that penetrate Earth's magnetic shield during geomagnetic storms, disrupting satellites and communications.
A sudden influx of high-energy charged particles, primarily protons, that reach Earth's upper atmosphere and near-Earth space during solar eruptions or geomagnetic disturbances. These events occur when the Sun's magnetic field ejects particles toward Earth, and Earth's magnetosphere becomes weakened or disturbed, allowing more particles than usual to penetrate to low-Earth orbit and polar regions.
What this means in real life
When a solar flare erupts, a wave of energetic particles races toward Earth; if your GPS or airline communication system relies on satellites in that path, you might experience signal loss or navigation errors for minutes to hours.
What it isn’t
Not the same as a solar flare itself—a flare is the initial explosion on the Sun's surface, while an energetic particle event is the arrival of the particles it ejects at Earth, which can happen hours or days later.
Commonly misused online
Often conflated with 'solar storm' or 'geomagnetic storm' as if they're identical; in reality, a geomagnetic storm is the disturbance to Earth's magnetic field, while an energetic particle event is the actual particle influx that may or may not cause a severe storm.
Based on 2 reference sources, including primary sources. Last verified July 16, 2026.