Space weather events linked to nuclear testing

Posted: May 18, 2017 by oldbrew in atmosphere, Electro-magnetism, research, solar system dynamics, weather
Tags: ,


One high-altitude nuclear test even managed to create its own artificial aurora. Others knocked out orbiting satellites.

Our Cold War history is now offering scientists a chance to better understand the complex space system that surrounds us, says Phys.org.

Space weather — which can include changes in Earth’s magnetic environment— is usually triggered by the sun’s activity, but recently declassified data on high-altitude nuclear explosion tests have provided a new look at the mechanisms that set off perturbations in that magnetic system.

Such information can help support NASA’s efforts to protect satellites and astronauts from the natural radiation inherent in space. From 1958 to 1962, the U.S. and U.S.S.R. ran high-altitude tests with exotic code names like Starfish, Argus and Teak.

The tests have long since ended, and the goals at the time were military. Today, however, they can provide crucial information on how humans can affect space.


The tests, and other human-induced space weather, are the focus of a comprehensive new study published in Space Science Reviews.

“The tests were a human-generated and extreme example of some of the space weather effects frequently caused by the sun,” said Phil Erickson, assistant director at MIT’s Haystack Observatory, Westford, Massachusetts, and co-author on the paper. “If we understand what happened in the somewhat controlled and extreme event that was caused by one of these man-made events, we can more easily understand the natural variation in the near-space environment.”

By and large, space weather – which affects the region of near-Earth space where astronauts and satellites travel – is typically driven by external factors. The sun sends out millions of high-energy particles, the solar wind, which races out across the solar system before encountering Earth and its magnetosphere, a protective magnetic field surrounding the planet.

Most of the charged particles are deflected, but some make their way into near-Earth space and can impact our satellites by damaging on-board electronics and disrupting communications or navigation signals. These particles, along with electromagnetic energy that accompanies them, can also cause auroras, while changes in the magnetic field can induce currents that damage power grids.

The Cold War tests, which detonated explosives at heights from 16 to 250 miles above the surface, mimicked some of these natural effects. Upon detonation, a first blast wave expelled an expanding fireball of plasma, a hot gas of electrically charged particles. This created a geomagnetic disturbance, which distorted Earth’s magnetic field lines and induced an electric field on the surface.

Some of the tests even created artificial radiation belts, akin to the natural Van Allen radiation belts, a layer of charged particles held in place by Earth’s magnetic fields.

Continued here.

Comments
  1. oldbrew says:

    Source: May 17, 2017
    NASA’s Van Allen Probes Spot Man-Made Barrier Shrouding Earth
    http://www.nasa.gov/feature/goddard/2017/nasas-van-allen-probes-spot-man-made-barrier-shrouding-earth

  2. JB says:

    One of the many misnomers and oxymorons of modern science: magnetic field LINES.
    Webster: “Physics a region, volume, or space where a specific, measurable force, as gravity or magnetism, exists ”

    A section of farm land may have visible lines. But magnetic fields do not have lines. They consist of a gradient in the force.

  3. oldbrew says:

    JB – as someone said, magnetic field lines are a concept. Not a 3D observable reality.

    An analogy might be the contour lines on a map. Go outside and you’ll never see them.

  4. ren says:

    It wasn’t until the 1970s, after the advent of satellites, however, that these ‘Birkeland currents’ were confirmed by direct measurements in space.

    Upward and downward current sheets
    These currents carry up to 1 TW of electric power to the upper atmosphere – about 30 times the energy consumed in New York during a heatwave.

    They are also responsible for ‘aurora arcs’, the familiar, slow-moving green curtains of light that can extend from horizon to horizon.

    While much is known about these current systems, recent observations by Swarm have revealed that they are associated with large electrical fields.

    Heated ions travel upward
    These fields, which are strongest in the winter, occur where upwards and downwards Birkeland currents connect through the ionosphere.



    http://www.esa.int/Our_Activities/Observing_the_Earth/Swarm/Supersonic_plasma_jets_discovered

  5. Brett Keane says:

    oldbrew says:
    May 18, 2017 at 4:23 pm: But you can see them as sheep tracks. Sheep aren’t fools, and they make lovely flat ground on hillsides. The steeper the better, like terraces. Might have given people the idea.

    ren says:
    May 19, 2017 at 5:48 pm: Thanks Ren, very clear, but still mysterious?

  6. Ben Vorlich says:

    I remember as a teenager in the 1960s there being a big fuss about an American Test in near space and talk about the Van Allen radiation belts, I can’t remember what the scare was though. It was the first time I heard about Van Allen.

    oldbrew says:
    May 18, 2017 at 4:23 pm: The Parallel Roads of Glen Roy? Also Lake Missoula in USA I think.

  7. oldbrew says:

    Brett – so the trick is to find the magnetic equivalent of sheep 😉

    Ren – re. aurora arcs: ‘While much is known about these current systems, recent observations by Swarm have revealed that they are associated with large electrical fields.’

    No magnetism without electricity:

    ‘A magnetic field is the magnetic effect of electric currents and magnetic materials.’
    ‘Magnetic fields can be produced by moving electric charges’
    http://en.wikipedia.org/wiki/Magnetic_field

    Auroras – see ‘Appearance and relation to magnetism’ here…
    http://www-spof.gsfc.nasa.gov/Education/aurora.htm

    Quote: Some auroras are deep red, and these may be just a shapeless glow–or they may have rays, too. And second, the direction of those rays is related to the magnetism of the Earth. [bold added]

  8. oldbrew says:

    Explorer 4 was an American satellite launched on July 26, 1958. It was instrumented by Dr. James van Allen’s group. The Department of Defense’s Advanced Research Projects Agency had initially planned two satellites for the purposes of studying the Van Allen radiation belts and the effects of nuclear explosions upon these belts (and the Earth’s magnetosphere in general), however Explorer 4 was the only such satellite launched as the other, Explorer 5, suffered launch failure.

    http://en.wikipedia.org/wiki/Explorer_4

  9. ren says:

    Magnetic field sources.

  10. oldbrew says:

    NASA mission uncovers a dance of electrons in space
    May 18, 2017

    You can’t see them, but swarms of electrons are buzzing through the magnetic environment—the magnetosphere—around Earth. The electrons spiral and dive around the planet in a complex dance dictated by the magnetic and electric fields. When they penetrate into the magnetosphere close enough to Earth, the high-energy electrons can damage satellites in orbit and trigger auroras. Scientists with NASA’s Magnetospheric Multiscale, or MMS, mission study the electrons’ dynamics to better understand their behavior. A new study, published in Journal of Geophysical Research revealed a bizarre new type of motion exhibited by these electrons.

    Electrons in a strong magnetic field usually exhibit a simple behavior: They spin tight spirals along the magnetic field. In a weaker field region, where the direction of the magnetic field reverses, the electrons go free style—bouncing and wagging back and forth in a type of movement called Speiser motion. New MMS results show for the first time what happens in an intermediate strength field. Then these electrons dance a hybrid, meandering motion—spiraling and bouncing about before being ejected from the region. This motion takes away some of the field’s energy and it plays a key role in magnetic reconnection, a dynamic process, which can explosively release large amounts of stored magnetic energy.

    “MMS is showing us the fascinating reality of magnetic reconnection happening out there,” said Li-Jen Chen, lead author of the study and MMS scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.

    Read more at: http://phys.org/news/2017-05-nasa-mission-uncovers-electrons-space.htm

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