U.S. tests ways to sweep space clean of radiation after nuclear attack
(Las Alamos Laboratory) Relativistic electrons can oscillate above the Earth trapped in the radiation belts (known as the Van Allen Belts).
These electrons, which can originate from the solar wind or a high-altitude nuclear explosion, have the potential to damage satellites in low-Earth orbit. For example, in 1962, the US detonated the Starfire warhead at an altitude of about 400 km. The unexpected resulting enhancement of the radiation belts disabled several satellites within a few months and energetic electrons remained in the radiation belts for up to several years. In order to address this potential vulnerability, schemes have been proposed to drain electrons from the radiation belts, with the most promising based on using high-power radio waves to couple to the electrons. There is additional urgency to understand the underlying physics behind remediating these belts with recent geo-political events occurring on the Korean peninsula.
(Science) Physicists have tested using the U.S. Navy’s very low frequency (VLF) antenna towers, powerful facilities used to communicate with submarines, says Dan Baker, director of the Laboratory for Atmospheric and Space Physics at the University of Colorado, Boulder, and a lead investigator on the Van Allen Probes. The antennae of the High-frequency Active Auroral Research Program in Alaska and the giant dish of the Arecibo Observatory in Puerto Rico might also be enlisted to generate cleansing radio beams.
…A team of scientists at Los Alamos and NASA’s Goddard Space Flight Center is spearheading a second experiment in VLF precipitation. In April 2021, the team plans to launch a sounding rocket carrying the Beam Plasma Interactions Experiment, a miniature accelerator that would create a beam of electrons, which in turn would generate VLF waves capable of sweeping up particles….
A third experiment would coax the atmosphere itself to kick up turbulent waves that would draw down electrons. In the summer of 2021, the Naval Research Laboratory plans to launch a mission called the Space Measurements of a Rocket-Released Turbulence. A sounding rocket will fly into the ionosphere—an atmospheric layer hundreds of kilometers up that’s awash in ions and electrons—and eject 1.5 kilograms of barium atoms. Ionized by sunlight, the barium would create a ring of moving plasma that emits radio waves: essentially a space version of a magnetron, the gadget used in microwave ovens.
…Whatever the technology, it could bring risks. A full-scale space cleanup might dump as much energy into the upper atmosphere as the geomagnetic storms caused by the Sun’s occasional eruptions. Like them, it could disrupt airplane navigation and communication. And it would spawn heaps of nitrogen oxides and hydrogen oxides, which could eat away at the stratospheric ozone layer. “We don’t know how great the effect would be,” says Allison Jaynes, a space physicist at the University of Iowa.