Sri Aurobindo
Letters of Sri Aurobindo
Volume I - Part 1
Fragment ID: 9777
That is the original Tapoloka in which the principle is Chit and its power of Tapas, but there are other worlds of Tapas on the other planes below. There is one in the mental, another in the vital range. It is one of these Tapas worlds from which the being you saw must have come.