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Energy conversion boundaries

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Presentation on theme: "Energy conversion boundaries"— Presentation transcript:

1 Energy conversion boundaries

2 neutrals and ions

3 Ionospheric Layers

4 Ionospheric Layers Effective dynamo ~ dayside E-layer
E: dynamo (only electrons can move freely due to i-n collision)  EM energy to Joule heating & geomagnetic induction F: highest density (highest energy absorption of solar EUV) but i-n collision is not sufficient  important for ion escape D: lowest layer of EUV heating (below is mesosphere with low-temperature)  mixing to non-mixing

5 Electron Density due to EUV
< nm The conductivity at a given height is proportional to the electron number density Ne. In the dynamo region the ionospheric plasma is largely in photochemical equilibrium. The dominant plasma species is O+2, which is produced by photo ionization at a rate J (s−1) and lost through recombination with electrons. N = √(J α-1 cos(χ))

6 E-layer as energy conversion boundary

7 Solar-Quiet (Sq) day ionospheric current system @ E-layer
. Morning Evening A current system in the ionosphere is created and maintained by solar EUV radiation The magnetic effect of this system was what George Graham discovered

8  since semi-static energy balance determines location of layer, it is strongly affected by the other element such as precipitating particles.

9 irregularity by precipitation

10 irregularity by precipitation
Ne Te Ti Vi 36 hour data (EISCAT)

11 Atmospheric surfaces

12 Mesopause: stratified structure to possible convection layer
 UV absorption by O3 below Tropopause: highest boundary of convection  UV absorption by O3 above It is not composition or force balance but the form of energy conversion that determines the mesopause/tropopause  dynamics/convection can easily modify the boundary

13 spin-off: Chapman-Ferraro current

14 spin-off: Chapman-Ferraro current
If the motor-dynamo transition is considered as ”boundary layer”, the cusp is the kind of boundary layer from dayside interaction to nightside interaction.  ion dynamic can modify the boundary location

15 deceleration makes a pair of J//
 We don’t need acceleration part to produce a pair of charge

16 detecting motion of “boundary” cusp
Newell et al., 2010, JGR

17 Mass-loading boundary
Plasma mantle is the largest source of the field-aligned current  solar wind is decelerated there inside the magnetopause  we need deceleration mechanism: due to mixture of escaping ions! Due to 16 time heavier mass of O+ than H+. the mass-loading of 0.1 cm-3 O+ to 10 cm-3 magnetosheath flow results in about 14% (=16/116) loss of velocity.

18 Mass-loading boundary
Therefore, the Earth’s plasma mantle can be considered as boundary from magnetospheric ion regime to solar wind ion regime, which is equivalent to mass-loading. To have plasma mantle “mass-loading” boundary layer, escaping ions is inevitable, and this could be the reason why we have not found the plasma mantle for the Martian “cusp”


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