物理
等离子体
悬浮
掐
磁场
湍流
磁流体力学
计算物理学
偶极子
磁铁
原子物理学
机械
核物理学
量子力学
作者
A.C. Boxer,R. Bergmann,J.L. Ellsworth,D. Garnier,J. Kesner,M. E. Mauel,P. Woskov
出处
期刊:Nature Physics
[Springer Nature]
日期:2010-01-24
卷期号:6 (3): 207-212
被引量:101
摘要
The rearrangement of plasma as a result of turbulence is among the most important processes that occur in planetary magnetospheres and in experiments used for fusion energy research. Remarkably, fluctuations that occur in active magnetospheres drive particles inward and create centrally peaked profiles. Until now, the strong peaking seen in space has been undetectable in the laboratory because the loss of particles along the magnetic field is faster than the net driven flow across the magnetic field. Here, we report the first laboratory measurements in which a strong superconducting magnet is levitated and used to confine high-temperature plasma in a configuration that resembles planetary magnetospheres. Levitation eliminates field-aligned particle loss, and the central plasma density increases markedly. The build-up of density characterizes a sustained turbulent pinch and is equal to the rate predicted from measured electric-field fluctuations. Our observations show that dynamic principles describing magnetospheric plasma are relevant to plasma confined by a levitated dipole. Turbulence usually makes plasmas more homogeneous. But in an unusual device for which the confining field is generated by a levitated half-tonne superconducting magnet, a study finds that turbulent fluctuations can actually increase the density of a plasma by driving diffusion against a density gradient.
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