A 2.45-GHz Microwave Air Plasma Under a Double-Hexapole Magnetic Field

Presented here is an image of a microwave air plasma produced from a 2.45-GHz source. To assist in the plasma ignition and confinement, a set of samarium-cobalt (Sm-Co) permanent magnets arranged in a double-hexapole configuration is used. In the image presented, air in the vacuum chamber is ignited into the plasma at a pressure of 3 × 10 -3 torr. The plasma exhibits a distinct pattern where brighter areas appear at alternate regions of magnetic cusps. Based on particle-in-cell simulations, the bright areas coincide with regions where the electron energies and electron densities are relatively high.