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Space Weather Alert - 17 March 2015

What Has Happened?

 

A chart showing current estimated global geomagnetic activity (Kp)

Magnetogram from Eskdalemuir Observatory showing the arrival of the CME at 04:46UT.


A coronal mass ejection (CME) has arrived at Earth sparking a geomagnetic storm. This geomagnetic storm is ongoing and if this continues for the next few hours there is a chance for an auroral display in parts of the UK and Europe.

The CME arrived at Earth 04:46UT on 17th March. Deviations of 45nT in horizontal activity (H) and 17 min in declination (D) were seen at Eskdalemuir observatory in the Scottish borders.

Shortly after auroral displays were seen across North America and New Zealand.

The CME originated from close to the centre of the solar disc on 15th March, associated with C9 solar flare. High-wind speeds from coronal holes may also be contributing to the increase in activity.

Assuming clear dark skies, there is an increased chance of seeing the aurora on the evening of the 17th-18th March. Those in Scotland, northern England and Northern Ireland will have the best chances - depending on if the current level of activity continues.

 

 

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Glossary

BGS
The British Geological Survey is one of the Natural Environment Research Council's Research Centres.

CME or Coronal Mass Ejection
The eruption of a portion of the outer atmosphere of the Sun into space, caused by rapid changes in its magnetic field. Often occurs along with a solar flare.

Coronal Hole
A region in the Sun’s outer atmosphere (corona) where hot material can flow unrestrained by its magnetic fields out into space.

 
Solar Flare
Energy released by the explosive reorganisation of magnetic fields within the Sun's atmosphere.

High Speed Stream
A fast moving stream of solar wind, responsible for magnetic storms.
 

Magnetogram
The variation, minute by minute, of the strength and direction of the Earth’s magnetic field. Measured in units of nano-Tesla (for the strength of the field) or in degrees (direction of the field).

Solar Wind
The ever-present expansion of the Sun’s hot outer atmosphere into the solar system, which carries space weather within it.