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  • Kansas Legislator Proposes Bill to Outlaw Sustainability Education
    A bill has been introduced in the Kansas legislature this week that would prohibit the promotion of ...Read more

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    Kansas Legislator Proposes Bill to Outlaw Sustainability Education

    A bill has been introduced in the Kansas legislature this week that would prohibit the promotion of sustainability. Here is a link to the one-page bill: http://www.kslegislature.org/li/b2013_14/measures/documents/hb2366_00_0000.pdf. See report on Bloomberg News.
  • Earth's Center Is 1,000 Degrees Hotter Than Previously Thought, Synchrotron X-Ray Experiment Shows
    Scientists have determined the temperature near the Earth’s center to be 6000 degrees Celsius, 1000 ...Read more

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    Earth's Center Is 1,000 Degrees Hotter Than Previously Thought, Synchrotron X-Ray Experiment Shows

    Scientists have determined the temperature near the Earth’s center to be 6000 degrees Celsius, 1000 degrees hotter than in a previous experiment run 20 years ago. These measurements confirm geophysical models that the temperature difference between the solid core and the mantle above, must be at least 1500 degrees to explain why the Earth has a magnetic field. For more information about this study, see the press release from the European Synchrotron Radiation Facility.
  • Ocean Volcanic Rocks Contain Samples of Recycled Crust
    Scientists have long believed that lava erupted from certain oceanic volcanoes contains materials fr...Read more

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    Ocean Volcanic Rocks Contain Samples of Recycled Crust

    Scientists have long believed that lava erupted from certain oceanic volcanoes contains materials from the early Earth’s crust. But decisive evidence for this phenomenon has proven elusive. New research from a team including Carnegie’s Erik Hauri demonstrates that oceanic volcanic rocks contain samples of recycled crust dating back to the Archean era 2.5 billion years ago. Their work is published in Nature. Oceanic crust sinks into the Earth’s mantle at so-called subduction zones, where two plates come together. Much of what happens to the crust during this journey is unknown. Model-dependent studies for how long subducted material can exist in the mantle are uncertain and evidence of very old crust returning to Earth’s surface via upwellings of magma has not been found until now. For more information about these results, see the press release from the Carnegie Institution.

Charged Particle Motion in Earth's Magnetosphere

Magnetic Mirroring and the Loss Cone

A particle's pitch angle increases as it moves into a region of stronger magnetic field and decreases as it moves into a region of weaker field.

In a simple magnetic mirror geometry the magnetic field reaches a minimum value at the center of the geometry and a maximum value at the end. Particles within such a geometry can follow a range of trajectories, as described below.

stuck in the center

A particle with pitch angle cannot move into a region of stronger magnetic field, so a particle with (at the center of the magnetic mirror, where B = Bmin) cannot move away from the center of the mirror.

straight and narrow

On the other hand, a particle with pitch angle is free to move anywhere and readily travels out of the magnetic mirror.

trapped in the mirror

In a magnetic mirror geometry, particles with pitch angles in the following range are trapped within the magnetic mirror:

into the loss cone

However, particles with are said to be in the loss cone and can escape the magnetic mirror.

Last modified May 16, 2005 by Randy Russell.

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