In today’s technologically driven world, people are more and more dependent on tools that are sensitive to electromagnetic interference. One early-observed space influence was with telegraph communication lines. During active space weather and because of the charged atmosphere, no battery was needed to operate the telegraph. Another classic space weather effect involved trans-Atlantic telephone lines, where severe space weather resulted in an amplification of voices in one direction and a dampening in the opposite direction, making conversation more difficult.
Today, changes in the space environment affect a variety of human activities. Rapid fluctuations in the plasma currents above the atmosphere, called sub-storms, can induce current spikes in long conducting wires at the surface. In power grid systems, these spikes can result in destruction of transformers and power outages. In pipelines, it is the slow recovery of the storm that causes problems, increasing corrosion and shortening the life of the equipment.
Plasma conditions also influence different types of radio wave communications, which either pass through or reflect off of the upper atmosphere. With changing plasma conditions, the radio signals can be distorted or redirected, resulting in lost connections or altered information. One example of this problem is reduced accuracy of the position derived from GPS units; a second is loss of radio contact between air traffic control and pilots, causing planes to be rerouted to alternate fly routes.
The particles in the plasma itself can also do damage. High-energy particles can penetrate materials and damage sensitive electronic equipment. When high-energy particles interact with matter, a trail of charges is created in their path. This excess of charges can then alter the electronics. One cosmic-ray-induced high-energy particle at ground level is energetic enough to alter a number in your computer; this is called a “bit-flip.” Some of the risk can be minimized by incorporating protective designs and by using correction algorithms in computers. By placing electronics in space, the risk to the electronics increases significantly, and these “single event effects” can even destroy components.
Individual particles are not the only source of problems. When many charged particles accumulate on the surface or inside a spacecraft, unwanted charging can occur. If discharge occurs, the current it creates can weaken or even destroy spacecraft parts. The charge accumulation can take hours to days; if the charges cannot bleed away fast enough, a discharge may occur.
Finally, high-energy particles can affect human tissues, and any space activity involving humans must consider potential radiation exposure to astronauts. What exposure levels the astronauts will encounter depends on where they will be traveling.
At LASP, we are focused on describing the space environment, understanding the dynamics, and studying the space climate. This information can then be used to predict when and where severe space weather will occur.
The following websites are examples of how we can make quantitative real-time forecasts for radiation belt electrons: