|a sudden severe disturbance of the earth's magnetic field, caused by emission of charged particles from the sun|
|Main Entry:||magnetic storm|
|Part of Speech:||n|
|Definition:||See geomagnetic storm|
A disturbance or fluctuation in the Earth's outer magnetosphere, usually caused by streams of charged particles (plasma) given off by solar flares. The entry of large amounts of plasma into the upper atmosphere results in intense auroral displays and other magnetic phenomena in the polar regions of the Earth. See also aurora.
disturbance of the Earth's upper atmosphere brought on by solar flares-i.e., bright eruptions from the visible portion of the Sun's chromosphere. The material associated with these flares consists primarily of protons and electrons with an energy of a few thousand electron volts. Called plasma, this material moves through the interplanetary medium at speeds ranging from 1,000 to 2,000 km (600 to 1,200 miles) per second, so that the ejected material reaches the Earth in approximately 21 hours. The pressure of the incoming plasma is transmitted to the outer edge of the Earth's magnetosphere; this causes an increase in the observed geomagnetic field at the ground, perhaps through hydromagnetic waves
Learn more about magnetic storm with a free trial on Britannica.com.