Laboratory study of magnetic reconnection with a guide field and density asymmetry across the current sheet

It has been known that the diamagnetic drift can stabilize the tearing mode, which is used to explain incomplete reconnection during sawtooth oscillations in Tokamaks [1]. Swisdak et al. propose that reconnection with a strong guide field and pressure asymmetry is suppressed when the relative drift speed between ions and electrons along the outflow direction exceeds the upstream Alfv\'{e}n speed [2]. Swisdak's argument has been supported by space observations [3], but the exact mechanism of suppression has not been conclusively verified. We will conduct experiments in MRX to study suppression of reconnection with a strong guide field and density asymmetry. We will apply a guide field strength of about 2--3 times of the reconnecting field and achieve a density ratio up to 10. By systematically changing the guide field strength, we will investigate how the electron diamagnetic drift can affect profiles of the magnetic/electric field and patterns of the ion/electron flow. Finally, we will study how these modified field profiles and flow patterns contribute to reduction of the reconnection rate. [1] B. Rogers and L. Zakharov, Phys. Plasmas 2, 3420 (1995). [2] M. Swisdak et al., J. Geophys Res. 108, A5 (2003). [3] T. D. Phan et al., Geophys. Res. Lett. 40, 11 (2013).