One of the four brainwave patterns, the alpha state is typified by patterns that repeat at the speed of 8-13 Hertz (cycles per second). People drifting into sleep or coming out of it are in the alpha state. It is also the speed of the brainwaves typified by daydreaming, a light trance, etc. This state becomes stronger when you close your eyes. The other brainwave patterns are beta, delta, and theta.