Stochastic Transition between Turbulent Branch and Thermodynamic Branch of an Inhomogeneous Plasma

Transition phenomena between thermodynamic branch and turbulent branch in submarginal turbulent plasma are analyzed with statistical theory. Time-development of turbulent fluctuation is obtained by numerical simulations of Langevin equation which contains submarginal characteristics. Probability density functions and transition rates between two states are analyzed. Transition from turbulent branch to thermodynamic branch occurs in almost entire region between subcritical bifurcation point and linear stability boundary.Comment: 10 pages, 8 figures, to be published in J. Phys. Soc. Jp

Transition Probability to Turbulent Transport Regime

Transition phenomena between thermal noise state and turbulent state observed in a submarginal turbulent plasma are analyzed with statistical theory. Time-development of turbulent fluctuation is obtained by numerical simulations of Langevin equation which contains hysteresis characteristics. Transition rates between two states are analyzed. Transition from turbulent state to thermal noise state occurs in entire region between subcritical bifurcation point and linear stability boundary.Comment: 9 pages, 6 figures, to be published in Plasma Phys. Control. Fusio

Nucleon-Nucleon Scattering in a Strong External Magnetic Field and the Neutrino Emissivity

The nucleon-nucleon scattering in a large magnetic background is considered to find its potential to change the neutrino emissivity of the neutron stars. For this purpose we consider the one-pion-exchange approximation to find the NN cross-section in a background field as large as $10^{15}\texttt{G}-10^{18}\texttt{G}$. We show that the NN cross-section in neutron stars with temperatures in the range 0.1-5 \texttt{MeV} can be changed up to the one order of magnitude with respect to the one in the absence of the magnetic field. In the limit of the soft neutrino emission the neutrino emissivity can be written in terms of the NN scattering amplitude therefore the large magnetic fields can dramatically change the neutrino emissivity of the neutron stars as well.Comment: 21 pages, 5 figures, to appear in PR

Cut loci and conjugate loci on Liouville surfaces

In the earlier paper (Itoh and Kiyohara, Manuscr Math 114:247–264, 2004), we showed that the cut locus of a general point on two-dimensional ellipsoid is a segment of a curvature line and proved "Jacobi’s last geometric statement" on the singularities of the conjugate locus. In the present paper,we showthat a wider class of Liouville surfaces possess such simple cut loci and conjugate loci. The results include the determination of cut loci and the set of poles on two-sheeted hyperboloids and elliptic paraboloids

A method to measure a relative transverse velocity of source-lens-observer system using gravitational lensing of gravitational waves

Gravitational waves propagate along null geodesics like light rays in the geometrical optics approximation, and they may have a chance to suffer from gravitational lensing by intervening objects, as is the case for electromagnetic waves. Long wavelength of gravitational waves and compactness of possible sources may enable us to extract information in the interference among the lensed images. We point out that the interference term contains information of relative transverse velocity of the source-lens-observer system, which may be obtained by possible future space-borne gravitational wave detectors such as BBO/DECIGO.Comment: 27 pages, 9 figures. Accepted for publication in Physical Review

Global parameter-space correlations of coherent searches for continuous gravitational waves

The space of phase-parameters (sky-position, frequency, spindowns) of a coherent matched-filtering search for continuous gravitational waves from isolated neutron stars shows strong global correlations (``circles in the sky''). In the local limit this can be analysed in terms of a parameter-space metric, but the global properties are less well studied. In this work we report on our recent progress in understanding these global correlations analytically for short to intermediate (less than a month, say) observation times and neglecting spindowns. The location of these correlation-circles in parameter-space is found to be determined mostly by the orbital velocity of the earth, while the spin-motion of the detector and the antenna-patterns only contribute significantly to the amplitude of the detection statistic along these circles.Comment: 10 pages, 6 figures; contribution to GWDAW9, submitted to CQ

Fossil shell in 3C 84 as TeV γ\gamma-ray emitter and cosmic-ray accelerator

We explore physical properties of the shocked external medium (i.e., a shell) in 3C 84 associated with the recurrent radio lobe born around 1960. In the previous work of Ito et al., we investigated a dynamical and radiative evolution of such a shell after the central engine stops the jet launching and we found that a fossil shell emission overwhelms that of the rapidly fading radio lobe. We apply this model to 3C 84 and find the followings: (i) The fossil shell made of shocked diffuse ambient matter with the number density of 0.3 cm$^{-3}$ radiates bright Inverse-Compton (IC) emission with the seed photons of the radio emission from the central compact region and the IC emission is above the sensitivity threshold of the Cherenkov Telescope Array (CTA). (ii) When the fossil shell is produced in a geometrically thick ionized plasma with the number density of $10^{3}$ cm$^{-3}$ and the field strength in the shell may reach about 17 mG in the presence of magnetic fields amplification and the radio emission becomes comparable to the sensitivity of deep imaging VLBI observations. A possible production of ultra high energy cosmic-rays (UHECRs) in the dense shocked plasma is also argued.Comment: 16 pages, 7 figures, 2 tables, ApJ, in pres

Problems with the Quenched Approximation in the Chiral Limit

In the quenched approximation, loops of the light singlet meson (the $\eta'$) give rise to a type of chiral logarithm absent in full QCD. These logarithms are singular in the chiral limit throwing doubt upon the utility of the quenched approximation. In previous work, I summed a class of diagrams, leading to non-analytic power dependencies such as \cond\propto m_q^{-\delta/(1+\delta)}. I suggested, however, that these peculiar results could be redefined away. Here I give an alternative derivation of the results, based on the renormalization group, and argue that they cannot be redefined away. I discuss the evidence (or lack thereof) for such effects in numerical data.Comment: (talk given at Lattice '92), 4 pages latex, 3 postscript figures, uses espcr2.sty and psfig.tex (all included) UW/PT-92-2