Magnetic Flux Analysis of the EAST Vertical Field

The relation between vertical field
${B}_{z}$
and normalized plasma density to the current
$\overline {n_{e}} / {I}_{p}$
on Experimental Advanced Superconducting Tokamak (EAST) is derived and the quasi-linearity between them is found in the flat-top phase of the elongated plasma current. The poloidal plasma pressure ratio
${\beta }_{p}$
is formulated to be proportional to
${n_{e}T}_{e}$
, the product of electron density
$n_{e}$
and temperature
$T_{e}$
. Thus
$\beta _{p}$
can be enhanced significantly by compressing the plasma to its outboard boundary by inserting a set of vertical field coils in the EAST vacuum chamber for highly shaped plasma, as suggested by Li and Gourdain. The additional vertical field will work under pulse mode in the flat-top phase and produce the horizontal compression field to improve
${n}_{e}$
and
${T}_{e}$
, and then realize a high
$\beta _{p}$
on EAST. Poynting’s theorem method is used for calculating the flux and evaluating the volt-second consumption in the EAST discharges. The analysis results show that the external flux is basically equal to the surface flux and only less than 10% of the total flux is consumed in resistive dissipation in typical EAST shots.