Saidar
From A Wheel of Time Wiki
Saidar is the female half of the One Power. Unlike the more violent saidin, saidar is said to be a "river of Power" which must be surrendered to or 'embraced' in order to gain control.
[edit] Saidar
Female channelers can tell when other women are touching the Source - a white glowing aura appears around their body, only visible to those trained to touch saidar. The ability can also be sensed in any woman capable of channeling, be they wilders or Aes Sedai. In the testing to see if you can channel, a woman channels a simple weave and waits. Within five minutes if a woman has the spark, the woman tries to channel the flow, and the test is confirmed. It takes longer for those who only can learn. However, a woman who has the spark can be detected by another female channeler without being tested.
Saidar is described as gentle, but infinitely powerful; a force which will do what you wish it to, but requires patience and submission to guide its power. Surrender is necessary to gain it, and women universally speak of it as 'embracing' the Power.
There is almost no way for a woman to tell when a man is channeling, though the residues of his channeling can be detected using an appropriate weave. Recently an active method was discovered to discern whether or not a man was channeling or holding saidin, but this is not widely known.
