The White Light

From Tardis Wiki, the free Doctor Who reference
The First Doctor regenerates. (TV: The Tenth Planet)

The White Light was a type of regeneration which typically occurred when a Time Lord's body was worn out. A simple glow enveloped the Time Lord, enabling the necessary change. (PROSE: How to be a Time Lord [+]Loading...{"chaptname":"Time Lord Regenerations","chaptnum":"5","1":"How to be a Time Lord (novel)"})

An example of this was the First Doctor's renewal. (TV: The Tenth Planet [+]Loading...["The Tenth Planet (TV story)"]) According to an early account, in which the process was more of a rejuvination of Dr. Who's youth, with the change to his personality being a side effect, this process was described as a "strange psychological storm". (PROSE: The Phoenix in the Tardis [+]Loading...{"page":"20","1":"The Phoenix in the Tardis (feature)"})