As a society we have come to depend on satellites, electrical power, and radio communication, all of which can be affected by these electric and magnetic forces. Sunspots, temporary disturbances in the Sun's photosphere, are the most visible advertisement of the solar magnetic field. They appear dark because temperatures are considerably lower than in surrounding areas. It results in sudden bursts of particle acceleration, heating of plasma to tens of millions of degrees, and the eruption of large amounts of solar mass. Large flares can cause electromagnetic problems for spacecraft, but are not thought to be responsible for geomagnetic storms.
Impulsive flares accelerate mostly electrons, with some protons.
They last minutes or hours and the majority appear near the solar equator. Impulsive flares occur at a rate of about 1000 per year during solar maximum. Gradual flares accelerate electrons, protons, and heavy ions to near the speed of light, and the events tend to last for days. They occur mainly near the poles of the Sun and happen about 100 times per year. Solar plumes are long, feathery jets that extend from near the poles of the Sun to more than 13 million miles into space.