The measurements by diamagnetic loops in EAST

•The theory of the measurement of the diamagnetic flux in EAST is introduced in this paper.•A good response between the diamagnetic flux measurements and rapid stored energy drop induced by ELMs.•Provide a simple and reliable method to study the plasma anisotropy in EAST. The measurement of the diamagnetic flux for poloidal beta and energy content of EAST based on diamagnetic loops is described in this article. The error sources can be well compensated with the diamagnetic loop and the compensation loop signals. And the maximum error of vacuum flux under experiments without plasmas is about 0.11 mWb, which meet the typical experimental requirements for high βp discharges (βp∼2.5). For ohmic discharges, the stored energy determined from the diamagnetic flux measurement Wdia is in good agreement with that from the equilibrium reconstruction Wmhd. After the auxiliary heating power are injected into plasmas, the increment of the energy content is observed to verify the heating effects of different heating systems. With the upgrade of 2021, the recent campaign has shown a good response between the diamagnetic flux measurements and rapid stored energy drop induced by edge localized modes (ELMs). The preliminary experimental results indicate that plasma anisotropic degree decreases with increasing density under operation conditions with high density and high heating power.