A Brief Overview
For many, space weather is a bit of a foreign concept: seemingly just a pairing of two unrelated words.
In reality, it is an important field that we are quickly learning to appreciate more and more in recent years due to its potential impact on the world’s infrastructure. Both the Strategic National Risk Assessment (SNRA), compiled by the United States Department of Homeland Security, and the National Risk Register, the UK’s official government assessment of significant potential national-wide risks, rank space weather among the most serious threats possible today. As if that doesn’t highlight its importance enough, this was the subject of President Barack Obama’s executive order as a nationwide call to brace for space weather. All this paints an ominous sounding picture, so let’s explore why all these experts are making such a big fuss.
At the broadest level, space weather describes the way in which the sun, and conditions in space more generally, impact human activity and technology both in space and on the ground. There are three main types of space weather phenomena that are usually of interest: solar flares (brief eruptions of intense high-energy radiation from the sun's surface), coronal mass ejections (large expulsions of plasma and magnetic field from the sun's corona), and solar energetic particles (which refers to the high energy particles coming from the sun that can cause geomagnetic storms). These type of events could cause widespread loss of RF communication, loss of power grid, loss/disruption of satellites, increases in background radiation, and much more.
A Carrington class storm (see below) could inflict damage and disruption estimated at between $0.6-$2.6 trillion in the United States alone — 20 times the cost of Hurricane Katrina! Major transformer damage/failure and permanent loss of generator step ups nationwide would take 4-10 years to recover from. The loss of electricity would ripple across the social infrastructure with water distribution affected within several hours, perishable foods and medications lost in 12-24 hours, loss of heating/air conditioning, sewage disposal, phone service, fuel re-supply and so on. At this point, that sounds apocalyptic, but one would be mistaken to assume that this is a rare occurrence.
The sun does all sorts of violent activities a few times each solar cycle, which is roughly 11 years. Statistically, Earth is likely to be hit by a Carrington class storm once every 100 years and a previous study in 2012 estimated chance of us getting hit by one in the next 10 years is 12%. If you take a look at Obama’s executive order, you can now probably understand why it says “It is the policy of the United States to prepare for space weather events to minimize the extent of economic loss and human hardship.”
In cases of severe terrestrial weather, like hurricanes and flooding, the last 25 years have seen quite the revolution in the understanding and management of risk, thanks to science and computer modelling. It’s clear that similar advances needs to be made in order to minimize “economic loss” and “human hardship” in the future. Really, all we can do is build better prediction models, which turns out to be quite difficult.
Space weather is filled with intricate interactions between many systems — the sun, solar wind, Earth's magnetic field, and Earth's atmosphere. All four of these systems each have their own complex mechanisms at play — electricity and magnetism, plasma dynamics, fluid mechanics, and the list goes on. Just as no one would expect to be able to predict weather in the lower atmosphere solely by observing the sun, predicting space weather in Earth’s upper atmosphere requires an understanding of how it responds to changes in the space environment.
Scientists have been working hard on these models for each system, and this is where ELFIN slots in. ELFIN’s primary and secondary science objectives are directly aligned with Goal #1 of the NASA Strategic Plan: Obj. 1.4 , to “Understand the Sun and its interactions with Earth, including space weather”. As mentioned in the Plan the Implementation Strategy for Obj. 1.4 is to carry out the National Academy’s 2012 Heliophysics Decadal Survey recommendation to “implement innovative research missions to understand how solar activity impacts Earth and fundamental physical processes important throughout the Universe by using space as a laboratory.” ELFIN’s primary and secondary science address all four Key Science Goals of the (2012) Heliophysics Decadal Survey to #1 “predict the variations in the space environment”, #2 “Determine the dynamics and coupling of Earth’s magnetosphere, ionosphere”, #3 “Determine the interaction of the Sun with the solar system” and #4. “Discover and characterize fundamental processes...”. The ELFIN spacecraft will directly perform in-situ measurements in Earth’s magnetosphere and confirm various mechanisms about Earth’s magnetic field and atmosphere’s dynamic response to geomagnetic substorms. These will then help scientists explain why particle fluxes behave the way they do during geomagnetic storms and ultimately allow us to build better forecast models.
Notable Space Weather Events for further reading…
The Carrington Event — September 1859
From Wiki: On September 1–2, 1859, one of the largest recorded geomagnetic storms (as recorded by ground-based magnetometers) occurred. Auroras were seen around the world, those in the northern hemisphere as far south as the Caribbean; those over the Rocky Mountains in the U.S. were so bright that the glow woke gold miners, who began preparing breakfast because they thought it was morning. People in the northeastern United States could read a newspaper by the aurora's light. The aurora was visible as far from the poles as south-central Mexico, Queensland, Cuba, Hawaii, southern Japan and China, and even at lower latitudes very close to the equator, such as in Colombia. Estimates of the storm strength range from −800 nT to −1750 nT. Telegraph systems all over Europe and North America failed, in some cases giving telegraph operators electric shocks. Telegraph pylons threw sparks. Some telegraph operators could continue to send and receive messages despite having disconnected their power supplies.
From Wiki and https://doi.org/10.1016/S0273-1177(97)01096-X: This geomagnetic storm has been estimated to be comparable in size to the current best estimate of the Carrington event. Auroras were seen near the equator in Samoa, and geomagnetically induced currents (GICs) caused fires at several telegraph stations in Sweden. Northern lights appeared in much of the eastern United States, creating brightly lit night skies. Telegraph service in the United States was slowed and then virtually eliminated around midnight of the 14th due to blown fuses, and damaged equipment. On the other hand, radio waves were strengthened during the storm due to ionosphere activation, allowing for some strong intercontinental reception. Electric lights did not seem to have been noticeably affected. Undersea cables also suffered from the storm. Damage to telegraph systems were also reported in Europe and the southern hemisphere.
From https://doi.org/10.1002/2016SW001423: An extreme solar flare and coronal mass ejection caused very significant radio blackouts, solar radiation storms, and a major geomagnetic storm. This caused a particularly significant disruption to communications, specifically to the military, and marked the start of a significant U.S. investment in space weather monitoring that continues to this day.
From Wiki: The largest geomagnetic storm of the space age causing the well‐known failure of the Quebec power grid and damaging two transformers in the United Kingdom. Some satellites in polar orbits lost control for several hours. GOES weather satellite communications were interrupted, causing weather images to be lost. NASA's TDRS-1 communication satellite recorded over 250 anomalies caused by the increased particles flowing into its sensitive electronics.The Space Shuttle Discovery was having its own problems: a sensor on one of the tanks supplying hydrogen to a fuel cell was showing unusually high pressure readings on March 13. The problem went away after the solar storm subsided.
This CME was not Earth directed and missed Earth by approximately 9 days, but was measured in situ by the STEREO‐A spacecraft. If this CME had been Earth directed, it would have generated a very severe Carrington class geomagnetic storm. It has been argued that this event should be used to create severe space weather scenarios for planning purposes.
More to come…