Publikace ÚTF

If an appropriate region of Kerr-Newman space-time is removed and suitable identificationsare made, the resulting space-time can be interpreted as an infinitely thin disk producing the original electromagnetic and gravitational fields. We choose the shape of the regions removed in such a way that radial pressures in the disks vanish. Even the very inner parts such as ergoregions may exist around the disks. The surface energymomentum tensor of the disks is checked to satisfy the weak and strong energy conditions. To emphasize the reality of these sources two models of the disks are presented: (i) rotating conductive charged rings which are supported against collapse by their internal pressure, (ii) two counter-rotating streams of charged particles moving along circular electro-geodesics. All these disk sources form a three-dimensional parameter space with specific electric charge Q/M, angular momentum a/M and the size of the excluded region being the parameters.