Spherical Tokamak Experiment

  • Research Topic: Spherical Tokamak Experiment

- Spherical Tokamak called Versatile Experiment Spherical Tokamak(VEST) will be constructed to investigate various ST research topics.

  • Spherical Tokamak

Spherical Tokamak(ST) is small compared to the conventional tokamak and has a high beta value of the benefits. However, ST has drawbacks not to have enough inner space to create a plasma due to the geometrical property. In lack of the inner space, it is not easy to use the method of conventional tokamak startup to use solenoid inside the center stack. Therefore it is difficult to make and maintain the initial plasma.

  • Versatile Experiment Spherical Tokamak(VEST)

The Versatile Experiment Spherical Tokamak (VEST) has been designed at Seoul National University in a unique configuration for partial solenoid operations as a new startup scenario. With partial solenoids located at both top and bottom inboard sides separately, two small plasmas are formed and merged into a tokamak plasma with low aspect ratio by resembling double-null merging startup. As specific scenario, two small 10kA small plasmas are made in at both top and bottom and merged in the middle part and then the main plasma is ramped up to 30kA in the first phase.

  • Applications of VEST

Various advanced fusion research topics will be studied in this device. It is one topics of the research to make initial plasma in ST that is known to the difficult problem compared to the conventional tokamak. Wave heating and high beta operation are possible topics to study in VEST. Because of many poloidal field coils, the divertor engineering including Super-X divertor is available subject. Magnetic reconnection physics from merging experiment which is not clearly demonstrated may be exciting theme.