Design and construction of Keda collisionless Reconnection eXperiment

The collisionless Keda Reconnection eXperiment (KRX) is a comprehensive platform for ground-base simulations of basic physical processes in a space environment. Its purpose is to reveal the triggering mechanism and electron diffusion structure of collisionless magnetic field reconnection and to study the associated plasma waves. The KRX is a linear device with a capsule-shaped vacuum chamber of 3 m diameter and composed of several sections. The world's largest oxide cathode source (2 m × 1 m) was used to produce a uniform background plasma. The KRX was surrounded by ten groups of guided field magnetic coils. Meanwhile, the reconnection magnetic field configuration was constructed using two parallel current plates with the same pulse current, which were installed on the upper and lower parts of the device. In addition, the pulse power supply adopted an H-shaped bridge structure to realize the controllable variable rate reconnection drive. More than 200 vacuum windows surround the device. The magnetic-field reconnection process can be measured using a probe array and other advanced optical diagnostics, including a THz polarimeter/interferometer and laser-induced fluorescence. KRX is the latest generation of magnetic-reconnection experiment platforms and is particularly useful for collisionless magnetic reconnection experiments. The reconnection area reaches 10 times the ion inertia length, and the Lundquist number is expected to reach 105. Global, active, and high-precision diagnostic measurements make multiscale, comprehensive research on magnetic field reconnection possible by addressing the shortcomings of satellite observations and numerical simulations. At present, the construction of the experimental platform and key components, such as diagnostics, have been completed. A research scheme of multi-scale, multi-magnetic island merger, 3D magnetic field reconnection, and other important issues is proposed based on the preliminary small-scale results of the research device.