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Charged particle beams held together or pinched by their self-magnetic fields have been of general interest since their earliest investigation by Bennett. The macroscopic picture of such a beam is that of a self-consistent magnetic confinement or compression against the expansion due to thermal pressure. On the microscopic scale, relativistic electrons in the magnetized beam are prodigious produces of synchrotron radiation.
An enhancement of the synchrotron power is achieved when the sum of the radial forces seen by the relativistic electrons is increased, as is the case when the azimuthal magnetic fields of neighboring pinches are present. A burst of synchrotron radiation is observed as shown in the experimentally recorded light in the figure below.
Figure. Top: Streak camera recording of the cross-sections of two adjacent pinched filaments, or Birkeland currents; time increasing from left to right. Bottom: Simulation cross sections of the plasma pinches. Also show is the synchrotron radiation recorded during the interaction of the pinches.
Because the burst of intense radiation occurs when the two pinches are separated, the synchrotron light, focused in the direction of the acellerating electrons, is that of two intense fowardly-directed ‘search lights’: a double synchrotron radiation source.
When scaled to the dimensions of a galaxy, each pinch having a diameter of 35 kpc, 10 kpc thick, separated initially 80 kpc apart, the synchrotron radiated power is of the order of 1037 watts, that is, the power recorded from double radio galaxies.
Figure. An isophotal comparison of the synchrotron intensities from quasars and double radio galaxies to the simulated interacting pinched plasma currents.
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The same selection of quasars and double radio galaxies but sorted according to the simulation radiation patterns. Time runs from top to bottom. The radiated power for the simulated radiation builds up rapidly reaching a maximum at about the second pattern from the top, then decreases. This is also true of the observed galaxies. The maximum power for observed and simulated galaxies is a few times 1037 watts. |
The concentric isobaric magnetic fields surrounding each plasma current produces a ‘magnetic hole’ or trap between the currents into which interstellar plasma is pushed. An example of two such swept up dusty plasmas colliding within the magnetic trap is shown below. The end result, several billion years later is a magnetic-field-free elliptical galaxy.
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Centaurus A. Overlay of optical ‘dust lane’ image on radio synchrotron isophotes. |
While the high-energy-density plasma experiment lasts but for a billionth of a second, as plasmas scale in size and parameter, the scaled plasma morphology for a galactic dimensioned interaction is about 10 billion years.
It should be noted that while the energy delivered to the pinch region is through a cylindrical or filamental current, the interaction region itself is that of two dusty plasmas, each 35 kpc in diameter and 10 kpc thick. After about 10 billion years, the morphology the interaction is that of a well-developed spiral galaxy.
‘The Evidence for Electrical Currents in Cosmic Plasma’, A. L. Peratt, IEEE Trans. Plasma Sci., Vol.18, pp.26-32, 1990.
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