CORONAL MASS EJECTIONS (CMEs)

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Facts about CMEs

• CMEs are massive plasma and magnetic field expulsions from the Sun's corona that propagate into interplanetary space.
• The Sun emits a massive amount of material, including electrons, protons, and heavier ions, as well as magnetic fields, during a CME. This material is expelled at great speeds into space.

Causes:

• CMEs are typically caused by the Sun's magnetic fields becoming unstable.
• The precise causes are unknown, although they frequently include the reconfiguration or rupture of magnetic loops on the Sun's surface.
• CMEs are separate from solar flares, though they frequently occur in tandem. Solar flares are brief bursts of energy and radiation, whereas CMEs are caused by the evacuation of solar material.

Impact on Earth:

• Geomagnetic Storms: Geomagnetic storms can occur as a result of the interaction of the CME's magnetic fields with the Earth's magnetosphere. These have the potential to interfere with satellite communications, navigation systems, and even power grids.
• Auroras: By energizing particles in Earth's atmosphere, CMEs can generate beautiful displays of the Northern and Southern Lights, popularly known as auroras.
• Radiation Risks: During a CME event, astronauts in space or passengers on high-altitude flights may be exposed to significant doses of radiation.

Important Solar Flare Facts:

• A solar flare is a powerful burst of radiation caused by the release of magnetic energy from sunspots.
• Flares are the most powerful explosive phenomena in our solar system.
• They appear as bright spots in the sun and can last anywhere from minutes to hours.
• They heat the material to many millions of degrees in a matter of minutes and emit a burst of radiation across the electromagnetic spectrum, including radio waves, x-rays, and gamma rays.
• Although solar flares can be seen in white light, their strong X-ray and ultraviolet emissions are generally more noticeable.
• The Impact of a Solar Flare on Earth: The powerful radiation emitted by a solar flare can interfere with satellite communications, distort radio transmissions, and even endanger humans in orbit.
• Furthermore, increasing solar radiation can generate geomagnetic storms, which can disrupt power systems and cause auroras (northern and southern lights) at lower latitudes.

What exactly is a geomagnetic storm?

• A geomagnetic storm is a significant disturbance in the magnetosphere of the Earth.
• These storms are caused by fluctuations in the solar wind, which cause large changes in the currents, plasmas, and fields in the Earth's magnetosphere.
• Sustained (for several hours) periods of high-speed solar wind and a southward-directed solar wind magnetic field (against the direction of Earth's field) near the dayside of the magnetosphere are effective for generating geomagnetic storms.
• The largest such storms are associated with solar coronal mass ejections (CMEs), where a billion tons or so of plasma from the sun, with its embedded magnetic field, arrives at Earth.

PRACTICE QUESTION What is coronal mass ejections? Describe the impact of Coronal Mass Ejections on Earth.