Solar winds have been long associated with geomagnetic storms but how exactly do they cause fearsome storms on Earth? This NASA explanation will shock you.
Solar winds are sinister phenomenons and have managed to stay under the radar for a long time. Reason is simple. Their role cannot be ignored when it comes to causing dangerous geomagnetic storms on Earth that can cause so much damage. Among the last three alarming geomagnetic storms that struck our planet recently, solar winds were responsible for causing two of them. And not only do solar winds bring these storms to Earth, they also intensify them and make them stronger and terrifying. But that is not all. It turns out these frightful solar winds are also capable of causing geomagnetic storms on Earth without the presence of coronal mass ejections (CME). So, how do solar winds cause geomagnetic storms? Read on to know the frightening explanation by NASA.
Solar winds are not really winds since space is entirely vacuum and air does not exist there. These ‘winds’ are powerful waves of plasma that are created in the corona of the Sun. They contain both solar particles as well as strong magnetic fields, according to NASA. Due to the extremely fast rotation speed of the Sun, the plasma winds up near the polar region, from where it escapes along the outwardly projecting magnetic field lines of the Sun and surrounds it in a sheath-like structure. What happens next is how it causes geomagnetic storms on Earth.
How solar winds propagates geomagnetic storms on Earth
Once the solar winds cover the Sun in a sheath, two things happen. Internally, the building up of magnetic fields on the Sun give the plasma an outward push and at the same time the interstellar space medium creates an inward pull due to the magnetic field. As a result, the plasma gets released into outer space in a shockwave and begins moving at an extremely high speed.
Now, the winds that move in the direction of Earth will also carry any CME that is headed towards us and give both speed and intensity. The intensity comes from its own magnetic field which combines with the CME to cause a stronger geomagnetic storm on Earth.
But during the periods of solar minimum, when CME discharges are less frequent, these menacing solar winds strike the magnetosphere of the Earth and cause small cracks in it through a process called co-rotating interaction region (CIR) and leave our planet temporarily vulnerable to solar radiation. The solar winds push inside the Earth’s magnetosphere and cause scary geomagnetic storms without even the presence of CME.