What is a substorm onset?

What is a substorm onset?

At substorm onset, the cross-tail. current sheet is disrupted, plasma is. energized, the plasma sheet expands, and the magnetic field relaxes to a. less tail-like configuration.

How long do substorms last?

Magnetospheric substorms usually last for a period ~ one to a few hours. During substorms there is an explosive release of stored magnetotail energy in the form of energetic particles (~ 5-50 keV) and strong plasma flows (~ 100-1000 km/s or so) and dissipated in the near-Earth nightside auroral region.

Why do substorms occur?

It was speculated [Borovsky et al., 1993; Belian et al., 1994] that randomly occurring substorms are associated with randomly occurring intervals of enhanced solar wind driving of the magnetosphere and that periodic substorms occur during time intervals when the solar wind driving of the magnetosphere is quasi- …

Why do auroral substorms occur?

As the first indication of the cause of substorms, (Fairfield and Cahill, 1966) found that polar magnetic disturbances associated with auroral substorms occur when the interplanetary magnetic field (IMF) has its southward component (-Bz).

What is the difference between geomagnetic storms and substorms?

The source of the magnetic disturbances observed at the Earth’s surface during geomagnetic storms is the ring current, whereas the sources of magnetic disturbances observed on the ground during substorms are electric currents in the ionosphere at high latitudes.

What is a solar storm and how does it affect Earth?

A solar storm is a disturbance on the Sun, which can emanate outward across the heliosphere, affecting the entire Solar System, including Earth and its magnetosphere, and is the cause of space weather in the short-term with long-term patterns comprising space climate.

Where do substorms originate in the Earth’s magnetosphere?

Some research suggests that substorms are triggered by magnetic field reconnection in the midtail region [e.g.10,11], which is also known as the near-Earth neutral line (NENL) model, or plasma instabilities, such as the cross-tail current instability, in the near-Earth tail resulting in cross-tail current disruption12 …

Can a solar storm destroy Earth?

Solar flares sound scary, but they won’t exactly destroy the Earth. The Sun’s occasional eruptions could reach our planet if they are especially powerful, and at that point may cause damage to power grids.