Researchers in Antarctic discover new facets of space weather

Posted: May 24, 2016 by oldbrew in atmosphere, Electro-magnetism, research
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Aurora over Antarctica [image credit: spacefellowship.com]

Aurora over Antarctica [image credit: spacefellowship.com]


ScienceDaily reports on the latest advances in understanding how the solar wind interacts with Earth. Note the seasonal aspects and the electric current findings.

A team of National Science Foundation (NSF)-supported researchers at the Virginia Polytechnic Institute and State University (Virginia Tech) discovered new evidence about how Earth’s magnetic field interacts with solar wind, almost as soon as they finished installing six data-collection stations across East Antarctic Plateau last January.

Their findings could have significant effects on our understanding of space weather. Although invisible to the naked eye, space weather can have serious, detrimental effects on modern technological infrastructure, including telecommunications, navigation, and electrical power systems.

The researchers for the first time observed that regardless of the hemisphere or the season, the polar ionosphere is subject to a constant electrical current, produced by pressure changes in the solar wind.

“This finding is a new part of the physics that we need to understand and work with,” said Robert Clauer, a professor in Virginia Tech’s Bradley Department of Electrical and Computer Engineering. “It’s a bit of a surprise, because when you have a current, you usually expect a voltage relationship, where resistance and current are inversely related — high resistance equals small current; low resistance equals large current.”

These space weather observations allow researchers to watch how the behavior of the sun and the solar wind — an unbroken supersonic flow of charged particles from the sun — changes over time and how Earth’s magnetic field responds to solar wind variations. The observations help build a detailed, reliable model of space weather.They hope that eventually space weather forecasting will become as reliable as today’s winter storm warnings.

The project to develop and deploy these autonomous data-collection stations in the Antarctic, funded by a $2.7 million NSF award, has progressed over a seven-year period. NSF manages the U.S. Antarctic Program, through which it supports researchers nationwide, provides logistical support to the research and operates three year-round stations in Antarctica.

Clauer and his team designed and hand-built six autonomous data-collection stations and installed them piece-by-piece near the geographic South Pole for initial testing. Following successful testing, the autonomous data-collection stations were placed along the 40-degree magnetic meridian (longitude), deep in the southern polar cap areas under the auroras. The stations, located in the harsh environment of the remote East Antarctic Plateau, are the Southern Hemisphere counterpart to a magnetically similar chain in Greenland.

Clauer and his Magnetosphere-Ionosphere Science team have been monitoring the electric current systems in the magnetosphere — specifically currents that connect to the ionosphere. During the summer in the Northern Hemisphere, there is more direct sunlight on the atmosphere, which means more atoms are ionized. This phenomenon creates a highly conductive ionosphere in the summer months and a poorly conductive one in the winter.

“The solar wind interacts with Earth’s magnetic field in a manner similar to a fluid, but an electrically conducting fluid,” Clauer said.

Full report: Researchers in Antarctic discover new facets of space weather — ScienceDaily

Comments
  1. oldbrew says:

    Related (study award): ‘The Role of Electric Fields in Plasma Structuring and Transport in the Mid-to High-Latitude Ionosphere’

    ABSTRACT
    ‘The solar wind, a continuous stream of solar plasma and magnetic fields blowing past the Earth, generates an electric field and causes a large-scale circulation of plasma within the magnetosphere. Earth’s magnetic field lines are “frozen” into the plasma and thus are entrained in this convection. Of particular interest, the feet of these convecting magnetic field lines thread the ionosphere (a layer of charged particles in the Earth’s upper atmosphere) at high latitudes and set the ionospheric plasma into motion as well, forming patterns of convection that change as the solar wind changes. At lower latitudes the ionospheric plasma co-rotates with the Earth. Disturbances in the solar wind associated with stormy space weather strengthen the convection in the magnetosphere, which has the effect of expanding the convection pattern in the ionosphere equatorward into regions where previously the ionospheric plasma was co-rotating. This project aims at improving knowledge of the portion of the expanded convection pattern in the mid-latitude region, where observations have previously been sparse, using a set of newly built radars. This is crucial to understanding space storms and their effects at Earth.’

    See more: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1524667

    The study runs until March 2018 (est.).

  2. gymnosperm says:

    And we learned the other day that the ring current is continuous…

  3. ren says:

    “We didn’t have a full picture of what was happening in the space environment because we could only observe one hemisphere, but magnetic field lines are connected to both hemispheres,” said Clauer. “It was important that we look at them simultaneously.”
    “The stations run autonomously and are powered by solar cells in the months-long Antarctic summer, and by lead-acid batteries during winter. The stations contain a collection of instruments, including a dual-frequency GPS receiver that tracks signal changes produced by DENSITY irregularities in the ionosphere, and two kinds of magnetometers that measure the varying strength and direction of magnetic fields.”
    The ionosphere extends into the mesosphere.

    Abstract
    A link between solar wind magnetic sector boundary (heliospheric current sheet) crossings by the Earth and the upper-level tropospheric vorticity was discovered in the 1970s. These results have been later confirmed but the proposed mechanisms remain controversial. Extratropical-cyclone tracks obtained from two meteorological reanalysis datasets are used in superposed epoch analysis of time series of solar wind plasma parameters and green coronal emission line intensity. The time series are keyed to times of maximum growth of explosively developing extratropical cyclones in the winter season. The new statistical evidence corroborates the previously published results (Prikryl et al., 2009). This evidence shows that explosive extratropical cyclones tend to occur after arrivals of solar wind disturbances such as high-speed solar wind streams from coronal holes when large amplitude magneto-hydrodynamic waves couple to the magnetosphere-ionosphere system. These MHD waves modulate Joule heating and/or Lorentz forcing of the high-latitude thermosphere generating medium-scale atmospheric gravity waves that propagate energy upward and downward from auroral zone through the atmosphere. At the tropospheric level, in spite of significantly reduced amplitudes, these gravity waves can provide a lift of unstable air to release the moist symmetric instability thus initiating slantwise convection and forming cloud/precipitation bands. The release of latent heat is known to provide energy for rapid development and intensification of extratropical cyclones.

    Highlights

    Extratropical cyclone tracks are obtained from the JRA-25 and ERA-40 re-analyses.

    Explosive extratropical cyclones tend to occur after arrivals high-speed solar wind streams.

    Auroral gravity waves may play a role in the release of instabilities leading to storms.
    http://www.sciencedirect.com/science/article/pii/S1364682616300967

  4. oldbrew says:

    ‘The researchers for the first time observed that regardless of the hemisphere or the season, the polar ionosphere is subject to a constant electrical current, produced by pressure changes in the solar wind.’

    It’s not clear how pressure ‘changes’ lead to a ‘constant’ current. Maybe they just mean continuous current.

  5. ren says:

    At an altitude of 26-27 km in the zone of the ozone very is clearly visible asymmetric distribution of ozone.

  6. ren says:

    Sorry 30 hPa is below 25 km.

  7. ren says:

    The reaction pressure in the troposphere occurs after about 10 days.


  8. ren says:

    Cho and co then used records from 76 meteorological stations around South Korea to study how the atmospheric pressure at sea level changed during these events.

    Sure enough, they found, on average, a small increase in pressure just after each high speed solar wind event. They reckon a fast solar wind increases the pressure by 2.5 hectoPascals. To put this in context, atmospheric pressure at sea level is about 1000 hPa. So that’s a tiny increase

    Despite the small number of events and the small change in pressure , these guys say their results are statistically significant.

    So what on Earth could be going on? How can the solar wind influence the atmospheric pressure at sea level?

    Let’s get some background info out of the way first. Atmospheric physicists have long known that the solar wind injects charged particles into the outer regions of the Earth’s atmosphere, the thermosphere, that stretches out to about 600km.

    This has a heating effect which causes the thermosphere to expand and contract. Since many satellites orbit at this height, including the International Space Station, these kinds of effects are important for determining how orbits degrade.

    But what of lower, denser parts of the atmosphere? The thinking is that during a Forbush decrease, these charged particles can penetrate further into the atmosphere. Here, the heating effect causes the atmosphere to expand. It is this that influences atmospheric pressure.

    Clearly the most extreme events will occur when a Forbush decrease occurs at the same time that the solar wind is at its most powerful. Which is exactly what the Korean team seem to have observed.

    To be sure, the effect is small at sea level but that won’t stop people speculating about the effect it could have over much broader areas than the Korean Peninsula. Charged particles are also thought to have a big impact on the rate of cloud formation, since their ionising effect can trigger water droplet formation

    Cho and co say they are already looking for bigger datasets concerning Forbush decreases and their effects over wider areas of the planet. The evidence that space weather can affect our is growing. It’ll be interesting to see what they find.
    https://www.technologyreview.com/s/424665/solar-wind-changes-atmospheric-pressure-over-south-korea/

  9. ren says:

    A cosmic ray destined to be detected by the Inuvik neutron monitor starts out heading for a point over the Pacific Ocean, west of Mexico. About 60,000 km away from Earth, the particle begins to experience effects of the Earth’s magnetic field, which deflects the particle towards Inuvik. The first interaction with an air molecule happens about 20 km above Inuvik.

    It has been proposed that cosmic ray monitors be equally spaced around the poles to achieve the best view into outer space. Inuvik is geographically well located to record cosmic rays and has the support services needed for a monitor.
    http://neutronm.bartol.udel.edu/listen/main.html

  10. oldbrew says:

    Powerful coronal mass ejection events from the young Sun may have provided the crucial energy needed to warm early Earth, according to a team of researchers led by Dr. Vladimir Airapetian of NASA’s Goddard Space Flight Center.
    http://www.sci-news.com/astronomy/young-suns-superflares-life-early-earth-03893.html

  11. ren says:

    Oldbrew
    “The free-floating nitrogen and oxygen combined into nitrous oxide, which is a powerful greenhouse gas. When it comes to warming the atmosphere, nitrous oxide is some 300 times more powerful than carbon dioxide.”
    This is very important in the changes of temperature in the upper stratosphere in the case of strong ionization.

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