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The slow pulsar (J0737-3039B) in the double pulsar system shows drifting features resulting from the emission from the millisecond pulsar in the system (J0737-3039A) interacting with B's magnetosphere. Using a geometrical model [8] that predicts the delay in B's features relative to A's radio pulses, we can constrain some of the properties of this system. We have developed a new methodology to isolate the drifting features from the general B emission. From this, we can determine the sense of rotation of A with respect to its orbit, estimate the altitude of the modulated emission from B due to A, and constrain the angle between the electromagnetic and radio beams. [ABSTRACT FROM AUTHOR]

The slow pulsar (J0737-3039B) in the double pulsar system shows drifting features resulting from the emission from the millisecond pulsar in the system (J0737-3039A) interacting with B's magnetosphere. Using a geometrical model [8] that predicts the delay in B's features relative to A's radio pulses, we can constrain some of the properties of this system. We have developed a new methodology to isolate the drifting features from the general B emission. From this, we can determine the sense of rotation of A with respect to its orbit, estimate the altitude of the modulated emission from B due to A, and constrain the angle between the electromagnetic and radio beams. [ABSTRACT FROM AUTHOR]

The giant flares produced by highly magnetized neutron stars, “magnetars,” are the brightest sources of high energy radiation outside our solar system. Serendipitous observations with NASA's Rossi X-ray Timing Explorer (RXTE) of the two most recent flares resulted in the discovery of high frequency oscillations in their X-ray fluxes. The frequencies of these oscillations range from ≈20 Hz to as high as 1800 Hz, and may represent the first detection of global oscillation modes of neutron stars. Here I will present an observational and theoretical overview of these oscillations and discuss how they might allow us to probe neutron star interiors and dense matter physics. [ABSTRACT FROM AUTHOR]

Voyager and Cassini plasma probe observations suggest that there are at least three fundamentally different plasma regimes in Saturn: the hot outer magnetosphere, the extended plasma sheet, and the inner plasma torus. At the outer regions of the inner torus some ions have been accelerated to reach energies of the order of 43 keV. Protons are the dominant species outside about 9 Rs, whereas inside, the plasma consists primarily of a corotating comet-like mix of water-derived ions with ∼3% N+. Over the A and B rings, an ionosphere —dominated by O2+ and O+ — can be observed. The energies of magnetospheric particles range from hundreds of keV to several MeV. Possible explanations to the observed high-energy population of particles involve the release of magnetic energy which heats the ion component of the plasma and then accelerates electrons to energies of some MeV. In this work we develop a model that calculates the acceleration of charged particles in the Saturn’s magnetosphere. We propose that the stochastic electric field associated to the observed magnetic field fluctuations is responsible of such acceleration. A random electric field is derived from the fluctuating magnetic field —via a Monte Carlo simulation— which then is applied to the momentum equation of charged particles seeded in the magnetosphere. Taking different initial conditions, like the source of charged particles and the distribution function of their velocities, we find that particles injected with very low energies (0.103 eV to 558.35 eV) can be strongly accelerated to reach much higher energies (8.79 eV to 9.189 keV) as a result of 200,000 hitting events. The components of the final velocity in the perpendicular direction to the corotation velocity (z-axis) show a bimodal behavior in their distribution. A possible consequence of this acceleration is the radial transport of the particles due to their gain of kinetic energy. It is, when the particle’s final energy surpasses the escape energy (in Saturn it ranges from 6.57 eV for protons to 91.33 eV for N+) the particle is able to be radially transported to the outer regions of the magnetosphere. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

A model for a pulsar magnetosphere is formulated based on oscillatory pair creation associated with large-amplitude oscillations of an electric field, E∥, parallel to the magnetic field. The amplitude is large enough for a typical particle (electron or positron) to become highly relativistic before slowing down, reversing its direction of motion and becoming highly relativistic propagating in the opposite direction. The maximum particle energy is above the threshold for effective pair creation, and pair creation is restricted to phases near this maximum. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]