Source of Sunquakes is Submerged beneath Solar Surface

Ultra-impulsive acoustic emission from a solar flare recently detected by NASA’s Solar Dynamics Observatory (SDO) indicated submersion of its source beneath the active region that hosted the flare.

Sunquakes release acoustic energy in the form of waves that ripple along the Sun’s surface, like waves on a lake, in the minutes following a solar flare.

Solar astronomers have long suspected that sunquakes are driven by magnetic forces or heating of the outer atmosphere, where the flare occurs.

These waves were thought to dive down through the Sun’s surface and deep into its interior.

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. Image credit: NASA / JPL-Caltech / GSFC / JAXA.

Flaring, active regions of the Sun are highlighted in this image combining observations from several telescopes.

High-energy X-rays from NASA’s Nuclear Spectroscopic Telescope Array (NuSTAR) are shown in blue; low-energy X-rays from Japan’s Hinode spacecraft are green; and extreme ultraviolet light from NASA’s Solar Dynamics Observatory (SDO) is yellow and red.

All three telescopes captured their solar images around the same time on April 29, 2015.

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Image credit: NASA / SDO.

Left frame shows the active region of the Sun in visible light (amber) and extreme ultraviolet (red) on July 30, 2011.

Right frame shows the ripples on Sun’s outlying surface up to 42 min after the onset of the flare, which is marked by the label ‘IP’ for impulsive flare.

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Solar flares may seem like far-away events, but they can damage satellites and even ground-based technologies and power grids.

Every 11 years, as the sun reaches its maximum activity they become bigger and more common, and that increases the chances that one will significantly affect Earth.

This imagery captured by NASA’s Solar Dynamics Observatory shows a solar flare and a subsequent eruption of solar material that occurred over the left limb of the Sun on November 29, 2020.

From its foot point over the limb, some of the light and energy was blocked from reaching Earth – a little like seeing light from a lightbulb with the bottom half covered up.

Also visible in the imagery is an eruption of solar material that achieved escape velocity and moved out into space as a giant cloud of gas and magnetic fields known as a coronal mass ejection, or CME.

A third, but invisible, feature of such eruptive events also blew off the Sun: a swarm of fast-moving solar energetic particles. Such particles are guided by the magnetic fields streaming out from the Sun, which, due to the Sun’s constant rotation, point backwards in a big spiral much the way water comes out of a spinning sprinkler.

The solar energetic particles, therefore, emerging as they did from a part of the Sun not yet completely rotated into our view, traveled along that magnetic spiral away from Earth toward the other side of the Sun.