Salvakalpa samadhi is absorption in eternity to the point where there is no real concept of self but there's still a karmic chain. Nirvikalpa samadhi is absorption in nirvana; concepts of self and no-self go away completely.
Frederick LenzFor most persons, the mystical kundalini energy is easier to initially perceive, unless you're extremely sensitive. It's more of a rush, a flash. There's an electric quality to it, a burning heat.
Frederick LenzGain control of the mind and make it still, initially just during periods of meditation, but then throughout the day and throughout the night.
Frederick LenzThe kundalini runs through you. It runs through the ida and the pingala, the two nerve channels in the subtle body; but there's a central channel, the shushumna, which is blocked. When it runs through that, then you can use the mystical kundalini.
Frederick Lenz