About ESA
The European Space Agency (ESA) is Europe’s gateway to space. Its mission is to shape the development of Europe’s space capability and ensure that investment in space continues to deliver benefits to the citizens of Europe and the world.
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Find out more about space activities in our 23 Member States, and understand how ESA works together with their national agencies, institutions and organisations.
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Science & Exploration
Exploring our Solar System and unlocking the secrets of the Universe
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Enabling & Support
Making space accessible and developing the technologies for the future
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‘Listening’ in for energetic electrons with Solar Orbiter
The Sun is a very efficient particle accelerator. During solar flares, bursts of high-energy particles can be injected into interplanetary space. The Earth’s magnetic field and atmosphere protects us from most of the possible harmful effects of these particles. However, when it comes to future astronaut missions to interplanetary space, this protection becomes less effective and a prediction of these solar events becomes important.
Solar Orbiter’s Radio & Plasma Waves (RPW) instrument listens for the radio emission that the energetic electrons create. The energetic electrons create a perturbation of the solar wind that results in a Solar Type III radio burst.
This figure shows the first Type III burst observed by RPW. It took place on 6 May 2020, when Solar Orbiter was at roughly half the Earth’s orbital radius from the Sun. The burst starts at approximately 09:33 UT, when the accelerated electrons were still in the Sun’s outer atmosphere, known as the corona. It stops being visible at around 09:47 UT, by which time the electrons have reached a distance of around 40 solar radii.
Usually such detections are made by instruments that detect the electrons as they flow past the spacecraft. For example, the sister instrument EPD does this on Solar Orbiter. The radio technique used by RPW complements these abilities because it allows the detection of all solar electron events, even those not passing directly past the spacecraft.
Solar Orbiter is a space mission of international collaboration between ESA and NASA.
Listen to the Sun’s own radio station
Joining the dots of an energetic particle event
Solar Orbiter first images and measurements
Detecting a solar energetic particle event with Sola…
