Magnettialueet

Magnettialueet are the elongated parts of a planet’s magnetosphere that extend away from the Sun and are formed when the solar wind drapes and stretches the planet’s magnetic field on the night side. In the Earth’s case, the magnetotail reaches far into space, spanning several to tens of planetary radii, depending on solar wind conditions. The structure consists of two magnetotail lobes, where magnetic field lines run in opposite directions, separated by a thin central plasma sheet containing hotter, less dense plasma.

The lobes store magnetic energy and are relatively empty of dense plasma, while the plasma sheet in the middle carries a higher density of charged particles with a reversing magnetic field across the sheet. The tail also hosts a current sheet and, at times, a neutral line where magnetic reconnection can occur. Magnetic reconnection in the tail releases stored energy, accelerates particles, and creates structures such as plasmoids and bursty bulk flows that propagate tailward. These processes contribute to geomagnetic substorms and drive auroral displays.

Magnettialueet are a feature of magnetized planets exposed to the solar wind. In addition to Earth, other planets with intrinsic magnetic fields, such as Jupiter and Saturn, have magnetotails that vary greatly in size and complexity. The study of magnetotails employs in-situ spacecraft measurements, remote sensing of auroras, and modeling to understand energy transfer from the solar wind into the magnetosphere and its space-weather consequences.