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Saturday, 22 November 2014

Sun's magnetic field boosts lightning strikes across the UK

lightningThe number of lightning strikes across the UK has been significantly affected by solar activity, according to new research.
Scientists say the Sun's magnetic field is bending the Earth's own field, increasing our exposure to cosmic rays.
These rays are believed to increase the number of thunderclouds and trigger lightning bolts in some locations.
Over five years, the UK experienced 50% more strikes when the Earth's magnetic field was affected by the Sun.
Fields of influence
The manner is which lightning bolts are triggered has long puzzled scientists as the air is known to be a good insulator of electricity.
Something else needs to come into play to conduct the electrical charges built up in thunder clouds down to the ground.
Since the 1990s, researchers have speculated that the magnetic activity of the Sun could be linked to lightning on Earth.
Current theories hold that high energy particles called galactic cosmic rays provide the necessary link that lets the current flow into a lightning bolt.
This latest work suggests that the orientation of the Sun's magnetic field is playing a significant role in the number of strikes.
The researchers believe the field is like a bar magnet, so as our star spins around sometimes the field points towards the Earth and sometimes away.
"What we found was there is significantly more lightning in the UK when the field is pointing towards the Sun than when its pointing away which was surprising," said Dr Matt Owens from the University of Reading, the lead author on the study.
"What we think is happening is that the Sun's magnetic field is pulling or pushing on the Earth's field and that's letting energetic charged particles down into the atmosphere at different locations and the idea is that these actually trigger lightning."
"For lightning, you need a thin conducting channel like a wire, and galactic cosmic http://www.bbc.co.uk/news/science-environment-30103561rays can provide this thin column of ionisation in the atmosphere."READ MORE-

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