MPD Arc Thruster with a Permanent Magnet

对于稳态运行的MPD电弧推进器，放电电流不能像其准稳态对应物那样大。因此，由自感磁场产生的电磁加速效应不够大。克服该缺点的一种常见方法是通过螺线管线圈向放电区域施加外部磁场。然而，这种方法对于整个推进器系统来说不一定是最好的，因为伴随着其重量的增加和产生给定场所需的电源的增加。本研究的目的是克服这个问题，通过使用一个永久磁铁代替螺线管线圈，从而实现一个MPD推力器与高推力器的性能在典型的操作条件下得到的推力器的性能如下：当使用氩气作为推进剂，比冲为1000秒，放电电流为400 A。这意味着相当低的推力效率为4.5%。与此相反，当使用氢作为推进剂时，比冲和推力效率都随着放电电流的增加而增加。在放电电流为400 A时，获得了68 mN的推力、7700 s的比冲和25%的推力效率。这是可比的效率水平，是获得与普通推进器时，使用螺线管线圈。

With a steady-state operating MPD arc thruster, the discharge current cannot be made as large as is possible with its quasi-steady counterpart. As a result, the electromagnetic acceleration effect produced by the self-induced magnetic field is not large enough. One common approach to overcoming this drawback is to apply an external magnetic field to the discharge region by means of a solenoidal coil. However, this method is not necessarily the best for the thruster system as a whole because of the accompanying increase in its weight and addition of the power supply that is required to produce a given field. The purpose of this study is to overcome this problem through the use of a permanent magnet in place of a solenoidal coil and thereby achieve an MPD thruster with high thruster performance.The thruster performances obtained under typical operating conditions are as follows: When argon was used as the propellant, the specific impulse was 1000 sec at a discharge current of 400 A. That translates into a rather low thrust efficiency of 4.5 %. In contrast to this, when hydrogen was used as the propellant, the specific impulse and thrust efficiency both rose as the discharge current was increased. At a discharge current of 400 A, thrust of 68 mN, specific impulse of 7700 sec and thrust efficiency of 25 % were obtained. It is comparable to the level of efficiency that is obtained with ordinary thrusters when a solenoidal coil is used.