1,596 research outputs found
Reply to ``Comment on `Hole-burning experiments within glassy models with infinite range interactions' ''
This is a reply to the comments by Richter and Chamberlin, and Diezemann and
Bohmer to our paper (Phys. Rev. Lett. 85, 3448 (2000)). As further evidence for
the claims in this Letter, we here reproduce the nonlinear spectral
hole-burning experimental protocol in an equilibrated fully connected
spin-glass model and we exhibit frequency selectivity, together with a shift in
the base of the spectral hole.Comment: 1 page, two figures, to appear in Phys. Rev. Let
Thermal Evolution and Radiative Output of Solar Flares Observed by the EUV Variability Experiment (EVE)
This paper describes the methods used to obtain the thermal evolution and radiative output during solar flares as observed by the Extreme u ltraviolet Variability Experiment (EVE) onboard the Solar Dynamics Ob servatory (SDO). Presented and discussed in detail are how EVE measur ements, due to its temporal cadence, spectral resolution and spectral range, can be used to determine how the thermal plasma radiates at v arious temperatures throughout the impulsive and gradual phase of fla res. EVE can very accurately determine the radiative output of flares due to pre- and in-flight calibrations. Events are presented that sh ow the total radiated output of flares depends more on the flare duration than the typical GOES X-ray peak magnitude classification. With S DO observing every flare throughout its entire duration and over a la rge temperature range, new insights into flare heating and cooling as well as the radiative energy release in EUV wavelengths support exis ting research into understanding the evolution of solar flares
Global Energetics of Thirty-Eight Large Solar Eruptive Events
We have evaluated the energetics of 38 solar eruptive events observed by a
variety of spacecraft instruments between February 2002 and December 2006, as
accurately as the observations allow. The measured energetic components
include: (1) the radiated energy in the GOES 1 - 8 A band; (2) the total energy
radiated from the soft X-ray (SXR) emitting plasma; (3) the peak energy in the
SXR-emitting plasma; (4) the bolometric radiated energy over the full duration
of the event; (5) the energy in flare-accelerated electrons above 20 keV and in
flare-accelerated ions above 1 MeV; (6) the kinetic and potential energies of
the coronal mass ejection (CME); (7) the energy in solar energetic particles
(SEPs) observed in interplanetary space; and (8) the amount of free
(nonpotential) magnetic energy estimated to be available in the pertinent
active region. Major conclusions include: (1) the energy radiated by the
SXR-emitting plasma exceeds, by about half an order of magnitude, the peak
energy content of the thermal plasma that produces this radiation; (2) the
energy content in flare-accelerated electrons and ions is sufficient to supply
the bolometric energy radiated across all wavelengths throughout the event; (3)
the energy contents of flare-accelerated electrons and ions are comparable; (4)
the energy in SEPs is typically a few percent of the CME kinetic energy
(measured in the rest frame of the solar wind); and (5) the available magnetic
energy is sufficient to power the CME, the flare-accelerated particles, and the
hot thermal plasma
The Yarkovsky Drift's Influence on NEAs: Trends and Predictions with NEOWISE Measurements
We used WISE-derived geometric albedos (p_V) and diameters, as well as
geometric albedos and diameters from the literature, to produce more accurate
diurnal Yarkovsky drift predictions for 540 near-Earth asteroids (NEAs) out of
the current sample of \sim 8,800 known objects. As ten of the twelve objects
with the fastest predicted rates have observed arcs of less than a decade, we
list upcoming apparitions of these NEAs to facilitate observations.Comment: Accepted for publication by The Astronomical Journal. 41 pages, 3
figure
Technology Development for the Caltech Submillimeter Observatory Balanced Receivers
The Caltech Submillimeter Observatory (CSO) is located on top of Mauna Kea,
Hawaii, at an altitude of 4.2 km. The existing suite of facility heterodyne
receivers covering the submillimeter band is rapidly aging and in need of
replacement. To facilitate deep integrations and automated spectral line
surveys, a family of remote programmable, synthesized, dual-frequency balanced
receivers covering the astronomical important 180 - 720 GHz atmospheric windows
is in an advanced stage of development. Installation of the first set of
receivers is expected in the spring of 2012.
Dual-frequency observation will be an important mode of operation offered by
the new facility instrumentation. Two band observations are accomplished by
separating the H and V polarizations of the incoming signal and routing them
via folded optics to the appropriate polarization sensitive balanced mixer.
Scientifically this observation mode facilitates pointing for the higher
receiver band under mediocre weather conditions and a doubling of scientific
throughput (2 x 4 GHz) under good weather conditions.Comment: 12 pages, 17 figures; IEEE Terahertz Science & Technology, January
2012, Volume 2, Issue
Hole-burning experiments within solvable glassy models
We reproduce the results of non-resonant spectral hole-burning experiments
with fully-connected (equivalently infinite-dimensional) glassy models that are
generalizations of the mode-coupling approach to nonequilibrium situations. We
show that an ac-field modifies the integrated linear response and the
correlation function in a way that depends on the amplitude and frequency of
the pumping field. We study the effect of the waiting and recovery-times and
the number of oscillations applied. This calculation will help descriminating
which results can and which cannot be attributed to dynamic heterogeneities in
real systems.Comment: 4 pages, 8 figures, RevTe
Validity of the second law in nonextensive quantum thermodynamics
The second law of thermodynamics in nonextensive statistical mechanics is
discussed in the quantum regime. Making use of the convexity property of the
generalized relative entropy associated with the Tsallis entropy indexed by q,
Clausius' inequality is shown to hold in the range of q between zero and two.
This restriction on the range of the entropic index, q, is purely quantum
mechanical and there exists no upper bound of q for validity of the second law
in classical theory.Comment: 12 pages, no figure
Extreme Ultraviolet Variability Experiment (EVE) Multiple EUV Grating Spectrographs (MEGS): Radiometric Calibrations and Results
The NASA Solar Dynamics Observatory (SDO), scheduled for launch in early 2010, incorporates a suite of instruments including the Extreme Ultraviolet Variability Experiment (EVE). EVE has multiple instruments including the Multiple Extreme ultraviolet Grating Spectrographs (MEGS) A, B, and P instruments, the Solar Aspect Monitor (SAM), and the Extreme ultraviolet SpectroPhotometer (ESP). The radiometric calibration of EVE, necessary to convert the instrument counts to physical units, was performed at the National Institute of Standards and Technology (NIST) Synchrotron Ultraviolet Radiation Facility (SURF III) located in Gaithersburg, Maryland. This paper presents the results and derived accuracy of this radiometric calibration for the MEGS A, B, P, and SAM instruments, while the calibration of the ESP instrument is addressed by Didkovsky et al. . In addition, solar measurements that were taken on 14 April 2008, during the NASA 36.240 sounding-rocket flight, are shown for the prototype EVE instruments
Theory of Thermodynamic Magnetic Oscillations in Quasi-One-Dimensional Conductors
The second order correction to free energy due to the interaction between
electrons is calculated for a quasi-one-dimensional conductor exposed to a
magnetic field perpendicular to the chains. It is found that specific heat,
magnetization and torque oscillate when the magnetic field is rotated in the
plane perpendicular to the chains or when the magnitude of magnetic filed is
changed. This new mechanism of thermodynamic magnetic oscillations in metals,
which is not related to the presence of any closed electron orbits, is applied
to explain behavior of the organic conductor (TMTSF)ClO.Comment: 11 pages + 5 figures (included
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