SPARC: Campaign Information

POLAR view of Earth in UV

The POLAR spacecraft in orbit around Earth takes regular pictures of the ionization activity in the upper atmosphere around the North Pole. The readings in the image shown here may translate into auroral activity visible from locations on Earth below the orange ring.

In addition to light and heat, each day the Sun sends us a bit of itself. Particles from the Sun's outer atmosphere, or corona, are continuously being blown off into space, a storm of stellar detritus known as the solar wind. This wind is at such a high temperature that even atoms themselves are broken apart into their constituent ions and electrons, a state known as a plasma.

This storm of solar plasma flows through space much like a liquid, and it carries with it the Sun's magnetic field, transporting it the 93 million miles to Earth's vicinity. This transported magnetic field interacts with the Earth's magnetic field, or magnetosphere, flattening the magnetosphere on Earth's day side and dragging it away on Earth's night side into a tail that stretches for thousands of miles into space.

The charged stardust that bombards our planet--along with the Sun's ultraviolet rays and x-rays--serves to ionize, or charge, the upper reaches of Earth's atmosphere. This ionized region, the ionosphere, is one of the major foci of study for the SPARC research group.

ting_sv_smm1.gif (6059 bytes)

The TING model is a supercomputer simulation that assembles data into a prediction of the density of free electrons in the upper atmosphere. This TING image indicates heavy electron activity over northern Canada. The red line separates the high-resolution nested grid from the coarse global grid.

As you can readily demonstrate with a compass, the Earth has its own magnetic field. The lines of force from this field emerge at one pole, loop out through a wide arc of space, then reenter the Earth at the opposite pole. These magnetic lines of force funnel some of the arriving solar wind down into the lower atmosphere around the poles. Once there, this ionized stardust can interact with neutral gases, causing them to glow in a phenomenon known as the aurora borealis or the aurora australis--the Northern or Southern Lights.

The aurora are only some of the more flamboyant manifestations of solar interaction with the Earth's atmosphere. Solar storms can send such intense bombardments of electrons into our atmosphere that they build up high voltages along stretches of power lines, overloading circuits and causing blackouts. They can also interfere with all sorts of radio, television, and microwave communications signals. These are just a few of the reasons SPARC scientists are working to refine their predictive models of how events on the Sun's surface play themselves out above our heads here on Earth.

One tool SPARC researchers use to gather data on how this solar energy is transferred to our terrestrial environment is a global network of incoherent-scatter radars, or ISRs. These instruments send powerful radio waves into the ionosphere, then interpret the small fraction of the energy that is scattered back to the receivers. These ISRs are part of a set of more than a dozen ground-based and satellite-based observatories SPARC researchers can tune into for real-time data feeds. The incoherent-scatter radars--along with several high-frequency radars in the Super Dual Auroral Radar Network (SuperDARN) array--are marked on the map below.

Our knowledge of "space weather" events is primarily based on effects that have been and will continue to be felt upon our Earth and its surrounding atmosphere. Until recent years, causal events on the Sun were not well linked to effect phenomena on Earth. These solar events include vast storms on the Sun that launch enormous blasts of radiation and clouds of "sun-stuff" – electrons, protons, and other particles traveling at relativistic speeds. The reasons for these solar events is still not well understood, but the ejecta from the sun has some well known consequences at the Earth, as described below.

In the last few years, the space science research community has launched several spacecraft in an attempt to monitor the sun for causal phenomena, while we have integrated a suite of real-time monitoring capabilities on the Earth to observe and record effect phenomena. The SPARC project is a prime example of such integrated monitoring capabilities -- and only with the synergistic coupling of the computer science and space science communities has it become possible to begin to understand and appreciate some of the near-Earth effects of these solar phenomena in real-time. Such real-time monitoring of space weather events can help dramatically reduce the impact of these space-weather events on the tools our technological society has grown to rely on for its comfort and its safety.

How Does Space Weather Affect Daily Life on the Earth?

Headlines from across North America report on the damage of two Canadian communications satellites by an energetic solar storm in January of 1994. Click on the image for a larger version.

Satellite damage
Possibly the best known recent example of "space weather" related satellite damage occurred in January 1994. On January 20 to 21, two Canadian communication satellites were temporarily put out of service by the effects of a solar storm. These satellites control critical—sometimes life-saving--radio and telephone communications in the high Arctic. A real-time monitoring capability could prevent such satellite damage in the future simply by warning satellite controllers to switch off critical components before satellites are buffeted by solar storm debris.

Power grid blackouts
On March 13, 1989, the entire Hydro Quebec power system suffered a blackout. This event was directly traced to a solar disturbance that caused a great geomagnetic storm at the Earth -- aurora were seen as far south as California! These aurora are caused by precipitation of highly energetic electrons, but these are usually restricted to high latitudes. When the Earth's magnetic field is disrupted by intersection with solar ejecta, this precipitation moves toward the equator and can actually induce electric currents over long distances in transmission grids. This is what happened in Quebec, causing hundreds of millions of dollars of damage. The ability to monitor and predict solar-terrestrial interactions would give power companies a chance to take preventive measures before damage is done. thus saving property and lives that depend on a steady supply of electrical power.

Radio communications
Following solar outbursts, terrestrial radio communications can be severely degraded or even curtailed as high-energy solar particle impact with the Earth’s atmosphere. In November, 1997, an X-class solar flare generated highly relativistic solar protons with enough energy to penetrate to ground level at Thule Air Base in Greenland, an event that is recorded only a couple of times in a decade. No doubt, normal communications were disrupted. An early-monitoring system could provide critical advance warnings, especially at high latitudes.

Oil and natural gas pipelines
Pipelines are constructed of electrically conductive material. During terrestrial geomagnetic storms, currents can be induced along these pipelines, accelerating corrosion at joints and leading to premature failure.

Radiation damage and injury
Astronauts living aboard space stations will face the possibility of exposure to lethal levels of radiation following energetic solar storms. An advance warning capability based on routine monitoring of solar and terrestrial events would provide space-based personnel the chance to shelter themselves.

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