Marklund convection (after Göran Marklund) is a natural plasma convection process that takes place in filamentary currents, that may cause chemical separation. It may occur within a plasma with an associated electric field, that causes convection of ions and electrons inward towards a central twisting filamentary axis. A temperature gradient within the plasma will also cause chemical separation based on different ionization potentials.
The mechanism provides an efficient means to accumulate matter within a plasma . In a partially ionized plasma, electromagnetic forces act on the non-ionized material indirectly through the viscosity between the ionized and non-ionized material.
Alfvén writes that:
- ".. elements with the lowest ionization potential are brought closest to the axis, and form concentric hollow cylinders whose radii increase with ionization potential [..] The drift of ionized matter from the surroundings into the rope means that the rope acts as an ion pump, which evacuates the surroundings . Regions with extremely low densities can be produced in this way ."
- In my paper in Nature the plasma convects radially inwards, with the normal E x B/B2 velocity, towards the center of a cylindrical flux tube. During this convection inwards, the different chemical constituents of the plasma, each having its specific ionization potential, enter into a progressively cooler region. The plasma constituents will recombine and become neutral, and thus no longer under the influence of the electromagnetic forcing. The ionization potentials will thus determine where the different species will be deposited, or stopped in their motion."
- Marklund, G. T., "Plasma convection in force-free magnetic fields as a mechanism for chemical separation in cosmical plasma", Nature, vol. 277, Feb. 1, 1979, p. 370, 371 . See also "Steady State Models for Filamentary Plasma Structures Associated with Force Free Magnetic Fields (1978) Royal Institute of Technology, Stockholm (TRITA-EPP-78-09) ISSN: 0348-7539
- Anthony L. Peratt, Physics of the Plasma Universe, Chapter 4, Electric Fields in Cosmic Plasma, Section 4.6.3. "Marklund Convection And Separation Of Elements" (1992) Springer-Verlag
- Hannes Alfvén, "Sec. II.4.5 Theory of Magnetic Ropes" Cosmic Plasma (1981)
- Email correspondence with Ian Tresman, 8 Mar 2007