Sunday, May 15, 2022

A method to study mini-magnetospheres

A unique environment to study kinetic-scale, collisionless plasma physics in the laboratory.

A magnetosphere is a region around a planet dominated by the planet’s magnetic field. Earth’s magnetosphere is formed when the solar wind interacts with the Earth’s magnetic field.

While large planetary magnetospheres have been studied for decades, ion-scale “mini” magnetospheres can provide a unique environment to study larger planet-sized magnetospheres.

In a new study, scientists from Princeton, UCLA, and the Instituto Superior Técnico, Portugal, report a method to study smaller magnetospheres, sometimes just millimeters thick, in the laboratory. They developed a new experimental platform to study mini-magnetospheres on the Large Plasma Device (LAPD). Their platform combines the magnetic field of the LAPD with a fast laser-driven plasma and a current-driven dipole magnet.

The LAPD magnetic field offers a model of the solar system‘s interplanetary magnetic field. The laser-driven plasma models of the solar wind and the dipole magnet provide a model for the Earth’s inherent magnetic field. The motorized probe allows the system to scan in three dimensions by combining data from thousands of laser shots.

This setup allows scientists to vary and control the magnetic field and other parameters carefully.

An activated dipole magnet enables the detection of magnetopause, a vital factor in the formation of a magnetosphere. The experiments revealed that as the dipole magnetic field increases, the magnetopause gets larger and stronger.

Scientists used computer simulations to predict the effects of the magnetopause. This helps them understand and validate their experimental results more fully.

Scientists noted, “These simulations will also guide future experiments, including studies utilizing a cathode recently installed on the LAPD.”

Author Derek Schaeffer said“The new cathode will enable faster plasma flows, which will allow us to study the bow shocks observed around many planets.”

In future studies, scientists are planning to study magnetic reconnection, an essential process in Earth’s magnetosphere in which magnetic fields annihilate to release tremendous energy.

Credit: AIP Publishing

Journal Reference:

  1. D. B. Schaeffer et al. Laser-driven, ion-scale magnetospheres in laboratory plasmas. I. Experimental platform and first results. DOI: 10.1063/5.0084353


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