NZ likely to avoid impact of new solar storm
Solar storms this week have power grids in the United States and Europe on high alert, though New Zealand will likely avoid those effects.
Ahead of a second solar storm, set to peak this morning New Zealand time, warnings were issued to stabilise power grids against surges of electricity.
Solar flares from the sun can disturb the Earth’s magnetic field, causing geomagnetic storms. In 1989, a geomagnetic storm knocked out the Quebec power grid, causing a nine-hour blackout.
An electricity industry source said New Zealand’s national grid runs north to south, with little running east to west, so was at a ‘‘very low risk’’ from solar storms, because of that configuration.
Geomagnetically induced currents could either directly affect electricity in power lines or divert from the Earth’s surface into the lines, causing voltage fluctuations and less reliable power flow that could trip circuits.
A severe solar storm in November 2001, measured at eight on a scale from one to nine, set off alarms attached to South Island transformers and tripped circuits at Islington, near Christchurch, and Halfway Bush, but there was no loss of power.
In 2012, after a warning issued March 9, the system was unaffected by a magnitude-seven solar storm.
Not all solar storms are directed at the Earth, but when they are it is possible to predict when and how strongly they will arrive.
Scientists watching the Sun this week saw sun spots forming which resulted in solar flares and coronal mass ejections – when the Sun ejects some of its atmosphere into space. It takes almost two days for the coronal mass ejections to travel the 150 million kilometres to Earth.
Solar storms have the added bonus of creating intense auroras around the poles. This week photographers across the country have been capturing images of the Aurora Australis, especially in the lower South Island.
The southern and northern lights, Aurora Borealis, are caused by electrons colliding with the Earth’s upper atmosphere. Normally the Earth’s magnetic field guides the electrons to the poles, but during geomagnetic storms they expand away from the poles and can be visible at lower latitudes.
The sun goes through an 11-year cycle where activity peaks and troughs – 2014 was a ‘‘solar maximum’’ year, the high point of the cycle.
More research has been coming to light about the effects of geomagnetic storms. New Zealand research published last year drew a link between the storms and an increased risk of stroke.
Auckland University of Technology’s Dr Valery Feigin led the study, which found out of 11,000 people who had a stroke, it was 20 per cent more likely to occur on days with geomagnetic storms.