Solar Emissions and Us

The Sun is a very hostile, violent environment, which ejects huge amounts of hot material into the Solar System. The Earth has a magnetic field which protects us from these powerful emissions of radiation during normal Solar activity. This protection is weaker at the poles and so the Aurorae Borealis and Australis occur. However, rare events occur which are much more powerful than normal Space Weather.

Space Weather includes various different phenomena. Solar Wind, in which particles are constantly emitted on a day to day basis, does not adversely impact infrastructure. Solar Flares, however, are large eruptions of electromagnetic radiation, these happen somewhat rarely and can be accompanied by Coronal Mass Ejections (CMEs) which are large emissions of plasma and magnetic field from the Sun’s Corona. CMEs eject at least a billion kilograms of material.

The latter described events profoundly impact technology both in orbit and on the ground.

The Impact

The importance of satellites in our current lives is impossible to understate. From predicting weather and analysing climate change for agriculture, GPS navigation and communicating all over the globe, they play a vital role in our society. These satellites, and their insights, are at risk from Space Weather. Solar phenomena impact communications with satellites due to perturbations in the Ionosphere. They also damage sensitive electrical components, damage Solar panels and put astronaut lives at risk.

Solar Weather also impacts important systems and infrastructure on the ground. Radio communications use the Ionosphere to reflect communications, allowing them to reach past the horizon. Changes in the Ionosphere affect its absorption of radio waves and lead to possible radio blackout.  

The most concerning effect of Solar Weather on ground infrastructure is Geomagnetically-Induced Currents (GICs). Like their namesake suggests, this is when a current is induced in a conductor, for example a power line or oil pipeline, by the Earth’s magnetic field. These GICs are driven by geomagnetic disturbances resulting from Solar Weather.

  

The (all too recent) History

There are many examples of GICs causing damage. The most famous of which is the Carrington event which happened in September 1859. Telegraph communications around the globe failed. Operators were badly shocked by arcing electricity spewing out of the machines. Platinum contacts, with a melting point of over 1,700°C were close to melting. Even much later, the residual GICs were so powerful that operators could send messages with their telegraphs completely unplugged [1]. The aurorae caused were so bright and so far toward the equator that miners in the Rocky Mountains woke up and began their day before realising the Sun would not rise for many more hours.

Thankfully in the Victorian era technology was sparse and had little impact on the lives of those at the time. An event of this magnitude today would cripple electrical grids that were not adequately protected.

 A more recent and much less powerful Solar Flare and CME hit Earth in 1989 when transformers in Quebec’s power grid were damaged, this led to a power outage which caused $13.2 Million direct damage to infrastructure and an estimated economic loss of $2.9 Billion [2]. Another CME, similar in magnitude to the Carrington event, barely missed Earth in 2012. Had it erupted one week earlier the economic impact in the USA alone could have been up to $2.6 Trillion, impacting up to 40 million people for up to 2 years[3]. These enormous figures are similar to others found in literature which warn of the devastating impact of CMEs. The Human cost of losing power for an extended period is likely to be high as the lights in hospitals turn off and supply chains break down.

While these events are thankfully rare, they still warrant investigation into analysis and predictions of Space Weather. Most of these predictions are done via satellite on missions such as SOHO(Solar and Heliospheric Observatory) and SDO(Solar Dynamics Observatory). These satellites rely on coronanographs to determine eruption velocities and to track CMEs through space, yet during these events in orbit systems can go offline, so a ground based redundancy should be investigated. There have been some investigations as to the efficacy of ground based radio-astronomy to detect and track CMEs from the ground. This image below clearly shows that solar eruptions can be easily detected from ground based radiotelescopes, I helped to take it last Summer from the I-LOFAR station in Birr, Co. Offaly. The yellow trails are solar emissions detected by the telescope.