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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. 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.

  4. Ring current - Wikipedia

    en.wikipedia.org/wiki/Ring_current

    The ring current system consists of a band, at a distance of 3 to 8 R E, [1] which lies in the equatorial plane and circulates clockwise around the Earth (when viewed from the north). The particles of this region produce a magnetic field in opposition to the Earth's magnetic field and so an Earthly observer would observe a decrease in the ...

  5. Dynamo theory - Wikipedia

    en.wikipedia.org/wiki/Dynamo_theory

    A simple argument can be based on consideration of net effects. To create the magnetic field, the net electric current must wrap around the axis of rotation of the planet. In that case, for the term to be positive, the net flow of conducting matter must be towards the axis of rotation. The diagram only shows a net flow from the poles to the ...

  6. Alfvén's theorem - Wikipedia

    en.wikipedia.org/wiki/Alfvén's_theorem

    Informally, Alfvén's theorem refers to the fundamental result in ideal magnetohydrodynamic theory that electrically conducting fluids and the magnetic fields within are constrained to move together in the limit of large magnetic Reynolds numbers (R m)—such as when the fluid is a perfect conductor or when velocity and length scales are infinitely large.

  7. 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

  8. Debye length - Wikipedia

    en.wikipedia.org/wiki/Debye_length

    For deionized water at room temperature, at pH=7, λ B ≈ 1μm. At room temperature (20 °C or 70 °F), one can consider in water the relation: [15] = where κ −1 is expressed in nanometres (nm) I is the ionic strength expressed in molar (M or mol/L)

  9. Shocks and discontinuities (magnetohydrodynamics) - Wikipedia

    en.wikipedia.org/wiki/Shocks_and_discontinuities...

    Contact discontinuities are discontinuities for which the thermal pressure, the magnetic field and the velocity are continuous. Only the mass density and temperature change. Tangential discontinuities are discontinuities for which the total pressure (sum of the thermal and magnetic pressures) is conserved. The normal component of the magnetic ...