2,277 research outputs found
Temperature Structure of a Coronal Cavity
we analyze the temperature structure of a coronal cavity observed in Aug. 2007. coronal cavities are long, low-density structures located over filament neutral lines and are often seen as dark elliptical features at the solar limb in white light, EUV and x-rays. when these structures erupt they form the cavity portions of CMEs. It is important to establish the temperature structure of cavities in order to understand the thermodynamics of cavities in relation to their three-dimensional magnetic structure. To analyze the temperature we compare temperature ratios of a series of iron lines observed by the Hinode/EUv Imaging spectrometer (EIS). We also use those lines to constrain a forward model of the emission from the cavity and streamer. The model assumes a coronal streamer with a tunnel-like cavity with elliptical cross-section and a Gaussian variation of height along the tunnel len~th. Temperature and density can be varied as a function of altitude both in the cavity and streamer. The general cavity morphology and the cavity and streamer density have already been modeled using data from STEREO's SECCHI/EUVI and Hinode/EIS (Gibson et al 2010 and Schmit & Gibson 2011)
Universal relation between longitudinal and transverse conductivities in quantum Hall effect
We show that any critical transition region between two adjacent Hall
plateaus in either integer or fractional quantum Hall effect is characterized
by a universal semi-circle relationship between the longitudinal and transverse
conductivities, provided the sample is homogeneous and isotropic on a large
scale. This conclusion is demonstrated both for the phase-coherent quantum
transport as well as for the incoherent transport.Comment: REVTEX 3.0, 1 figure, 4 pages. SISSA-08179
Bulk Versus Edge in the Quantum Hall Effect
The manifestation of the bulk quantum Hall effect on edge is the chiral
anomaly. The chiral anomaly {\it is} the underlying principle of the ``edge
approach'' of quantum Hall effect. In that approach, \sxy should not be taken
as the conductance derived from the space-local current-current correlation
function of the pure one-dimensional edge problem.Comment: 4 pages, RevTex, 1 postscript figur
Genome of Diaporthe sp. provides insights into the potential inter-phylum transfer of a fungal sesquiterpenoid biosynthetic pathway.
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Previous issue date: 2017-02-0
Charge Density Wave in Two-Dimensional Electron Liquid in Weak Magnetic Field
We study the ground state of a clean two-dimensional electron liquid in a
weak magnetic field where lower Landau levels are completely filled
and the upper level is partially filled. It is shown that the electrons at the
upper Landau level form domains with filling factor equal to one and zero. The
domains alternate with a spatial period of order of the cyclotron radius, which
is much larger than the interparticle distance at the upper Landau level. The
one-particle density of states, which can be probed by tunneling experiments,
is shown to have a pseudogap linearly dependent on the magnetic field in the
limit of large .Comment: Several errors correcte
Edge state transmission, duality relation and its implication to measurements
The duality in the Chalker-Coddington network model is examined. We are able
to write down a duality relation for the edge state transmission coefficient,
but only for a specific symmetric Hall geometry. Looking for broader
implication of the duality, we calculate the transmission coefficient in
terms of the conductivity and in the diffusive
limit. The edge state scattering problem is reduced to solving the diffusion
equation with two boundary conditions
and
.
We find that the resistances in the geometry considered are not necessarily
measures of the resistivity and () holds only
when is quantized. We conclude that duality alone is not sufficient
to explain the experimental findings of Shahar et al and that Landauer-Buttiker
argument does not render the additional condition, contrary to previous
expectation.Comment: 16 pages, 3 figures, to appear in Phys. Rev.
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