[Regnum] A sudden, difficult to explain magnetic storm was observed on Earth on the night of September 10. The geomagnetic index jumped sharply without external influences, the press service of the solar astronomy laboratory of the Space Research Institute of the Russian Academy of Sciences (IKI RAS) reported.
The storm was absent from the forecasts made the day before, the color scale was completely green. After midnight Moscow time, the magnetosphere disturbance rose almost to the G2 mark, which means a storm of medium strength.
“Even in hindsight, it is completely impossible to understand what happened on Earth or near Earth that could have caused such a violent reaction of the magnetic field,” the experts noted.
Magnetic storms are usually caused by external impacts from the Sun, when plasma clouds or streams of fast solar wind from coronal holes reach the Earth. However, nothing came to the planet
[from the sun]
last night, the scientists explained.
They suggested that an unusually large substorm had occurred on Earth. In such a phenomenon, magnetosphere energy is released without any apparent external cause. As a rule, a substorm is caused by a spontaneous imbalance in the magnetosphere tail, which stretches behind the planet for more than 100 thousand km in the direction opposite to the Sun.
The version about a substorm is confirmed by spontaneous polar lights observed on Earth, the laboratory added.