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New Pulsar Emission Mechanism?

  1. Jan 7, 2010 #1
    In papers presented this week to the American Astronomical Society, Andrea Schmidt and John Singleton of Los Alamos National Laboratory provide detailed analyses of several pieces of observational data that suggest that pulsars emit the electromagnetic equivalent of the well-known "sonic boom" from accelerating supersonic aircraft. Just as the "boom" can be very loud a long way from the aircraft, the analogous signals from the pulsar remain intense over very long distances.

    Schmidt and Singleton's presentations provide strong support for a pulsar emission mechanism (the superluminal model) due to circulating polarization currents that travel faster than the speed of light. These superluminal polarization currents are disturbances in the pulsar's plasma atmosphere in which oppositely-charged particles are displaced by small amounts in opposite directions; they are induced by the neutron star's rotating magnetic field. Despite the large speed of the polarization current itself, the small displacements of the charged particles that make it up means that their velocities remain slower than light, so that Einstein's theory of Special Relativity is not violated. No laws of physics are broken in this model.

  2. jcsd
  3. Jan 9, 2010 #2
    Sigh..... I'm just waiting for this paper to be totally misinterpreted.

    It should be noted that in electromagnetic waves, it is *very common* for patterns to travel faster than light. One pretty trivial example, is imagine your television screen. It's very easy to move a dot across the screen in the screen that moves faster than light.

    The big no-no is to transmit information faster the light.
  4. Jan 14, 2010 #3
    Apparent Faster-Than-Light Pulse Propagation in Interstellar Space: A new
    probe of the Interstellar Medium

    "Radio pulsars emit regular bursts of radio radiation that propagate through the
    interstellar medium (ISM), the tenuous gas and plasma between the stars. Previously
    known dispersive properties of the ISM cause low frequency pulses to be delayed in
    time with respect to high frequency ones. This effect can be explained by the presence
    of free electrons in the medium. The ISM also contains neutral hydrogen which has a
    well known resonance at 1420.4 MHz. Electro-magnetic theory predicts that at such
    a resonance, the induced dispersive effects will be drastically different from those of
    the free electrons. Pulses traveling through a cloud of neutral hydrogen should undergo
    “anomalous dispersion,” which causes the group velocity of the medium to be larger than
    the speed of light in vacuum. This superluminal group velocity causes pulses containing
    frequencies near the resonance to arrive earlier in time with respect to other pulses.
    Hence, these pulses appear to travel faster than light.
    See http://arxiv.org/PS_cache/arxiv/pdf/0909/0909.2445v2.pdf
    Bob S
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