Tokamak Start-Up Modeling and Design for EAST First Plasma Campaign

Plasma start-up design and first plasma experiment in VEST

“…After successful current initiation with sufficient plasma breakdown, the equilibrium field should be provided for further I p evolution; the vertical field proportional to I p should be provided with decay index, n of 0-1.5 for the radial force balance with vertical stability as the plasma current develops [12][13][14][15]. Since it is not possible to provide high E t ·B t /B p for I p initiation and stable equilibrium field for I p ramp-up simultaneously, the plasma start-up generally starts with the formation of sufficient field null region followed by the stable equilibrium field.…”

“…The start-up design code is implemented based on the circuit approximation, which is widely used method for the estimation of eddy current in many devices [13][14][15][16]. The PF coils and vacuum vessel are discretized into multiple filaments with equivalent resistance and inductance.…”

“…In addition to the prediction of the vacuum field evolution, initial guess of I p evolution is required for the estimation of the required vertical field for the equilibrium. By introducing C Ejima , Ejima coefficient, for resistive consumption during ramp-up phase, I p evolution can be expressed as following [13,14,17]:…”

“…After field null region is formed, PF#6 and PF#9 provide the vertical magnetic field for radial force balance and the radial field for vertical stability using the single swing scheme. At the I p ramp-up phase, proper vertical and radial magnetic fields are provided for the force balance with vertical stability with 0 < n < 3/2 [12][13][14][15] as shown in Fig. 4(c) and (d).…”

Start-up phase plasma discharge design of a tokamak via control parameterization method

“…EAST is the first shaped tokamak of mega-ampere scale to achieve plasma utilizing a fully superconducting poloidal field coil system located in Hefei, China. [10] Parameters of EAST that we have used are listed in Table 2.…”