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  2. Birkeland current - Wikipedia

    en.wikipedia.org/wiki/Birkeland_current

    Schematic of the Birkeland or Field-Aligned Currents and the ionospheric current systems they connect to, Pedersen and Hall currents. [1]A Birkeland current (also known as field-aligned current, FAC) is a set of electrical currents that flow along geomagnetic field lines connecting the Earth's magnetosphere to the Earth's high latitude ionosphere.

  3. Plasma beta - Wikipedia

    en.wikipedia.org/wiki/Plasma_beta

    A common example is the interaction of the solar wind with the magnetic fields of the Sun [12] or Earth. [13] In this case, the betas of these natural phenomena are generally much smaller than those seen in reactor designs; the Sun's corona has a beta around 1%. [12] Active regions have much higher beta, over 1 in some cases, which makes the ...

  4. Magnetohydrodynamics - Wikipedia

    en.wikipedia.org/wiki/Magnetohydrodynamics

    Schematic view of the different current systems which shape the Earth's magnetosphere. In many MHD systems most of the electric current is compressed into thin nearly-two-dimensional ribbons termed current sheets. [10] These can divide the fluid into magnetic domains, inside of which the currents are relatively weak.

  5. Dynamo theory - Wikipedia

    en.wikipedia.org/wiki/Dynamo_theory

    A transport equation, usually of heat (sometimes of light element concentration): = + where T is temperature, = / is the thermal diffusivity with k thermal conductivity, heat capacity, and density, and is an optional heat source. Often the pressure is the dynamic pressure, with the hydrostatic pressure and centripetal potential removed.

  6. Ionospheric dynamo region - Wikipedia

    en.wikipedia.org/wiki/Ionospheric_dynamo_region

    In the height region between about 85 and 200 km altitude on Earth, the ionospheric plasma is electrically conducting. Atmospheric tidal winds due to differential solar heating or due to gravitational lunar forcing move the ionospheric plasma against the geomagnetic field lines thus generating electric fields and currents just like a dynamo coil moving against magnetic field lines.

  7. Mathematical descriptions of the electromagnetic field

    en.wikipedia.org/wiki/Mathematical_descriptions...

    An elegant and intuitive way to formulate Maxwell's equations is to use complex line bundles or a principal U(1)-bundle, on the fibers of which U(1) acts regularly. The principal U(1)- connection ∇ on the line bundle has a curvature F = ∇ 2 , which is a two-form that automatically satisfies d F = 0 and can be interpreted as a field strength.

  8. Earth's magnetic field - Wikipedia

    en.wikipedia.org/wiki/Earth's_magnetic_field

    This current reduces the magnetic field at the Earth's surface. [27] Particles that penetrate the ionosphere and collide with the atoms there give rise to the lights of the aurorae while also emitting X-rays. [28] The varying conditions in the magnetosphere, known as space weather, are largely driven by solar

  9. Plasmasphere - Wikipedia

    en.wikipedia.org/wiki/Plasmasphere

    The plasmasphere, or inner magnetosphere, is a region of the Earth's magnetosphere consisting of low-energy (cool) plasma. It is located above the ionosphere . The outer boundary of the plasmasphere is known as the plasmapause , which is defined by an order of magnitude drop in plasma density.