Sanavandi Hamid, Guo Wei
National High Magnetic Field Laboratory, 1800 East Paul Dirac Drive, Tallahassee, FL, 32310, USA.
Mechanical Engineering Department, FAMU-FSU College of Engineering, Florida State University, Tallahassee, FL, 32310, USA.
NPJ Microgravity. 2021 Oct 29;7(1):40. doi: 10.1038/s41526-021-00174-4.
Low-gravity environment can have a profound impact on the behaviors of biological systems, the dynamics of fluids, and the growth of materials. Systematic research on the effects of gravity is crucial for advancing our knowledge and for the success of space missions. Due to the high cost and the limitations in the payload size and mass in typical spaceflight missions, ground-based low-gravity simulators have become indispensable for preparing spaceflight experiments and for serving as stand-alone research platforms. Among various simulator systems, the magnetic levitation-based simulator (MLS) has received long-lasting interest due to its easily adjustable gravity and practically unlimited operation time. However, a recognized issue with MLSs is their highly non-uniform force field. For a solenoid MLS, the functional volume V, where the net force results in an acceleration <1% of the Earth's gravity g, is typically a few microliters (μL) or less. In this work, we report an innovative MLS design that integrates a superconducting magnet with a gradient-field Maxwell coil. Through an optimization analysis, we show that an unprecedented V of over 4000 μL can be achieved in a compact coil with a diameter of 8 cm. We also discuss how such an MLS can be made using existing high-T-superconducting materials. When the current in this MLS is reduced to emulate the gravity on Mars (g = 0.38g), a functional volume where the gravity varies within a few percent of g can exceed 20,000 μL. Our design may break new ground for future low-gravity research.
低重力环境会对生物系统的行为、流体动力学以及材料生长产生深远影响。对重力效应进行系统研究对于增进我们的知识以及太空任务的成功至关重要。由于典型太空飞行任务成本高昂且有效载荷大小和质量存在限制，基于地面的低重力模拟器已成为准备太空飞行实验以及作为独立研究平台不可或缺的工具。在各种模拟器系统中，基于磁悬浮的模拟器（MLS）因其重力易于调节且运行时间几乎不受限制而长期受到关注。然而，MLS存在一个公认的问题，即其力场高度不均匀。对于螺线管MLS，净力导致加速度小于地球重力g的1%的功能体积V通常为几微升（μL）或更小。在这项工作中，我们报告了一种创新的MLS设计，它将超导磁体与梯度场麦克斯韦线圈集成在一起。通过优化分析，我们表明在直径为8厘米的紧凑型线圈中可以实现超过4000 μL的前所未有的V。我们还讨论了如何使用现有的高温超导材料制造这样的MLS。当该MLS中的电流降低以模拟火星上的重力（g = 0.38g）时，重力在g的百分之几范围内变化的功能体积可以超过20,000 μL。我们的设计可能为未来的低重力研究开辟新的道路。
