Solar Wind Shear Could Affect Earth’s Magnetosphere.
Streaming out of our nearest star at speeds of 400 to 760 kilometers per second, the solar wind strips planets with no magnetic fields and shapes the magnetosphere of those that do.
In the case of the Earth, these highly-charged particles are deflected by the Lorentz force and shaped into a long, comet-like tail whose boundary is called the magnetopause. For many years scientists assumed some of these particles could penetrate inside our magnetic shield via the partial reconnection of the magnetic field lines. However, new research shows solar wind shear could be very responsible for shaping our Sun/Earth connection.
Understanding space weather is very important. It’s more than just preventing a sunburn or watching the aurora. Geomagnetic storms can affect power grids, reroute high-latitude air flights, cause errors of up to 46 meters in global positioning systems, interfere with satellite communications and endanger space missions and their crews. However, there is a lot more affecting Earth’s magnetosphere than just the periodic solar flare or coronal mass ejection. These hot plasma flows from the Sun produce shear – and it’s an affect that has been widely overlooked by mainstream studies.
“The solar wind is filled with strong current sheets and sudden velocity shears; often the two are co-located.” says Joseph E. Borovsky of the Space Science Institute, Boulder, Colorado, USA. “Sudden wind shear has a catastrophic effect on the magnetotail.”
According to the American Geophysical Union news release, Dr. Borovsky’s study was produced by combining statistical analysis of solar wind data from the Advanced Composition Explorer satellite, which measures solar particles approaching Earth, with a series of magnetohydrodynamic simulations, used to model the behavior of the Earth’s magnetosphere, Borovsky characterizes the properties of the shear layers that travel past the Earth and the reaction of the Earth to those passing layers.
“To explore the effects of sudden wind shears on the Earth’s magnetosphere, global magnetospheric MHD simulations with four different simulation codes are performed at the Community Coordinated Modeling Center (CCMC) with north-south and east-west wind shears.” explains Borovsky. “Windsock movement of the magnetotail is analyzed and comet-like disconnections of the magnetotail and magnetosheath are examined. Sudden changes in the cross-polar-cap potential and ionospheric Joule dissipation are seen as the shear layers pass the Earth.”
If you think this is just a transient event, then think again. Borovsky’s studies have shown that as many as 60 of these shear zones can pass by Earth each day at velocities above 50 kilometers per second. Each time they pass, they create a disturbance in the whole magnetosphere and ionosphere… a disturbance which could create a “comet-like disconnection” of the magnetotail. Even though it might not be responsible for a geomagnetic storm, the solar wind shear events may be responsible for how a solar storm is created.
Original Story Source: American Geophysical Union Press Release.
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