Reason for powerful geomagnetic storm March 17, 2015 do not understand to scientists - VIDEO PDF Print E-mail
Wednesday, 18 March 2015 23:59

Record in strength over the past four years, a magnetic storm on a planetary scale continues on Earth for more than a day. The first signs of strengthening of the geomagnetic field were registered on March 17 around 7 am Moscow time, when the geomagnetic index Kp, which are classified according to fluctuations in the earth's magnetic field, exceeded the level of 5 - the threshold after which the event is called a geomagnetic storm. About 9 am Moscow time the index rose to 6, and at about 3 pm abruptly increased to a value of 8, which corresponds to the magnetic storm one of the highest points, only 1 point inferior to the maximum value of the scale. Last time in the history of observations of such intensity perturbations observed about 4 years ago - 26 September 2011. Since Kp level never exceeds the value of 7.

Magnetic storms along with auroras - the most famous and powerful manifestation of the Sun's influence on Earth. Thus, if the aurora occur in the upper layers of the atmosphere and only at certain latitudes, the oscillations of the magnetic field are recorded in its entirety, both in space and on the surface, and even below the surface of the Earth, there are planetary in nature.

Storm is always a reaction to coming to Earth from space plasma clouds ejected from the Sun as a result of active events, often a solar flare. These clouds, which in addition to plasma (charged particles) and also contain their own magnetic field, causing the kinetic blow to Earth's magnetic field, performing the role of a shield. As a result of external impact the earth's magnetic field is out of balance, begins to waver, generate excess currents. In addition, the plasma cloud came saturate the surrounding space charged particles, dramatically increasing the radiation background in near space.

Phenomenon storms last from a few hours to 1-2 days sometimes, due to both the time required field of the Earth to return to equilibrium, and sizes come with giant clouds of plasma constituents sometimes tens of millions of kilometers. Thus the size of the cloud is often much greater than the size of the Sun, which is associated with their gas-dynamic expansion on the way from the Sun to the Earth.

Magnetic storms are generally divided into 5 levels, the first of which corresponds to the minimum fluctuations of the magnetic field with a deviation of the order of 70-120 nT from the average value of the magnetic field and the last fifth level, which is extremely severe storms accompanied by oscillations of the field with an amplitude of more than 550 nT . Last time a storm of higher fifth level was observed in the world almost 10 years ago - September 11, 2005 and was a reaction to one of the largest in the last decade of solar flares.

At that responded Earth at this time to say much more difficult. Over the last 4 days in the Sun, there was not a single flash and a perfect score even a single flash, which can be called a major most likely candidate for the source of the storm is the solar flare that occurred on March 15 at about 5 am Moscow time and is accompanied by a rather strong emission mass.

Meanwhile, the very flash, the originator of the storm, not even in the top ten events this year, not to mention the past 4 years, and the forecast for the event of such a force no one could give. Such a sharp reaction to the earth's magnetic field is relatively weak event was a surprise.

If a candidate is selected on the source of the storm is true, the plasma cloud took about 2 days to cover the distance of 150 million. Km from the Sun to the Earth, and they were moving at a speed of over 850 km / h, which is almost twice the normal speed component 400-500 km. The kinetic energy of the plasma, which depends quadratically on its velocity, thus higher than the normal four times, which, combined in some other factors could explain such a strong impact.

In general, in accordance with the classification of the National Service of the US magnetic storms fourth (penultimate level) can lead to the following consequences: (1) the impact on the energy system: voltage stability problems, the partial destruction of the energy systems and disabling protection systems; (2) the impact on the spacecraft: the surface charge and the problem of tracking and orientation; (3) the impact on terrestrial systems: induced currents in pipelines require protective measures, the occasional passage of HF radio waves, worsening of satellite navigation for a few hours, the failure of low-frequency radio navigation, and auroras visible to the tropics.

At present, the intensity of the oscillations of the magnetic field has decreased, but still remains high and is classified as an ongoing storm. The outlook on the return of the magnetic field in the unperturbed state is at 15-21 hours Moscow time.



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