Surface Charge Accumulation on PTFE under Magnetic Field

Polytetrafluoroethylene (PTFE) was employed to investigate the effect of magnetic field on surface charge accumulation. The magnetic field (B) was set to make E×B drift into, away from and parallel to sample surface. An electrostatic probe was designed to measure the surface charge density. The test results showed that surface charge distribution sharply depended upon the magnetic field. When E×B drifted into PTFE, charges deposited in intensive area of the surface, the max charge density was bigger than that without magnetic field. When E×B drifted away from PTFE, charges deposited forming a barrier shape with max charge density bigger than that when E×B drifted into PTFE. When E×B was parallel to PTFE, charge accumulation was flat with max charge density smaller than that without magnetic field. Furthermore, the max charge density increased by varying the magnetic flux density from 70 mT to 140 mT.