Corridor — Barbara Hambly

A novelette of 14,000 words - Sequel to Hambly's Windrose novels. An inter-dimensional transport corporation has run a trans-dimensional corridor through Los Angeles, and is powering it by draining the psychic energy of the population in its path, driving large numbers of people temporarily insane. Exiled wizard Antryg Windrose and his partner, computer programmer Joanna Sheraton, attempt to put a stop to this.