How does solar activity affect electrical systems on Earth?

We put this question to Chris Davis:

The reason is that when you have these magnetic fields releasing it releases an intense storm of particles. It's called a coronal mass ejection to scientists which is a very dull name for anything. Actually it's a billion tonnes of material travelling at a million miles an hour. It contains about 100 times the energy of the world's entire nuclear arsenal. Although it's spread out over an extremely wide region in space if that magnetic field is in the opposite sense than the magnetic field on Earth then we all know from school that magnets of opposite polarities attract. Magnets of similar polarities repel. If they're opposing polarity the two magnetic field can interact and that allows all this hot material to interact with the Earth's atmosphere .