We review plasma confinements in an open ended system including single mirror, tandem mirror, cusp and rotating plasma from the viewpoint of physical and technical requiremints for fusion. The thermal barrier and its effects are also explained.
The high magnetic field applicable to the gyrotron of millimeter wavelength is generated by the magnet device using superconducting coils and Cu coils. The main field intensity can be varied up to 40KG, which corresponds to the electron cyclotron frequency of 112GHz. The device has been applied successfully to 70GHz gyrotron.
Maximum pinch time of a plasma in a toroidal pinch device is obtained from magnetic probe measurement. This experimental result is in good agreement with the pinch time calculated from MHD shock wave model. It is verified that the model is very useful for an implosion of the pinch plasma.