EXTREME DYONIC BLACK-HOLES IN STRING THEORY

Supersymmetric extreme dyonic black holes of toroidally compactified h eterotic or type-II string theory can be viewed as lower-dimensional i mages of solitonic strings wound around a compact dimension. We consid er conformal sigma models which describe string configurations corresp onding to various extreme dyonic black holes in four and five dimensio ns. These conformal models have regular short-distance region equivale nt to a WZW theory with level proportional to magnetic charges. Argume nts are presented suggesting a universal relation between the black ho le entropy (area) and the statistical entropy of BPS-saturated oscilla tion states of solitonic string.