Current Flowing In Accretion Disk and State Transition of Black Hole Binaries

The state transition of black hole binaries is discussed based on the evolution of magnetic field configuration, and the latter is related closely to the current flowing in an accretion disk around a black hole. It turns out that the main characteristics of the transition from low/hard state to high/soft state can be fitted by invoking the transportation of current from the outer region to the inner region in accretion process.