How does the solar wind affect the Earth?

It affects it by the intense clouds of high energy particles that it often contains which are produced by solar storms. When these clouds, called coronal mass ejections, make their way to the Earth in 3-4 days, they collide with the magnetic field of the Earth and cause it to change its shape. The particles then leak through the magnetic field of the Earth, particularly near the north and south poles, and cause still more changes to the magnetic field of the Earth, this time at even lower altitudes closer to the ground. These changes can produce many problems with electrical equipment. The way on which solar wind 'plasma' invades the Earth's magnetic field and seeps into the inner regions where the van Allen radiation belts are located, is not very well known. Also, in the direction opposite the Sun, the Earth's magnetic field is pulled way out into interplanetary space making it look like a comet. In this 'geotail' region many different electrical disturbances take place that can accelerate particles to very high speeds and energies. All of this is made much more violent by the solar wind, especially the storm clouds that the Sun launches our way from time to time!