2,793 research outputs found
Wind direction azimuthal signature in the stokes emission vector from the ocean surface at microwave frequencies
Includes bibliographical references (page 431).An ocean polarimetric emission model is presented. It is found that skewness and upwind/cross-wind rms slopes are responsible for the first and second azimuthal harmonic, respectively. Atmospheric effects contribute significantly at low wind speeds, and at horizontal polarization at certain observation angles. Simulation results compare favorably with reported JPL-WINDRAD measurements
Black Branes in a Box: Hydrodynamics, Stability, and Criticality
We study the effective hydrodynamics of neutral black branes enclosed in a
finite cylindrical cavity with Dirichlet boundary conditions. We focus on how
the Gregory-Laflamme instability changes as we vary the cavity radius R. Fixing
the metric at the cavity wall increases the rigidity of the black brane by
hindering gradients of the redshift on the wall. In the effective fluid, this
is reflected in the growth of the squared speed of sound. As a consequence,
when the cavity is smaller than a critical radius the black brane becomes
dynamically stable. The correlation with the change in thermodynamic stability
is transparent in our approach. We compute the bulk and shear viscosities of
the black brane and find that they do not run with R. We find mean-field theory
critical exponents near the critical point.Comment: 23 pages, 3 figures. v2: added comments on first-order phase
transitio
M2-M5 blackfold funnels
We analyze the basic M2-M5 intersection in the supergravity regime using the
blackfold approach. This approach allows us to recover the 1/4-BPS self-dual
string soliton solution of Howe, Lambert and West as a three-funnel solution of
an effective fivebrane worldvolume theory in a new regime, the regime of a
large number of M2 and M5 branes. In addition, it allows us to discuss finite
temperature effects for non-extremal self-dual string soliton solutions and
wormhole solutions interpolating between stacks of M5 and anti-M5 branes. The
purpose of this paper is to exhibit these solutions and their basic properties.Comment: 19 pages, 5 figures, harvmac; typo corrected in equation (3.19
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