4,462 research outputs found
Q**2-dependence of semi-inclusive electron-nucleus scattering and nucleon-nucleon correlations
We analize semi-inclusive electron-nucleus processes e+A->e'+h+X at moderate
Q**2 and energy transfer nu. Our results show that nucleons bound in the
nuclear medium are distributed according to a function f_A that reduces to the
standard light-cone distribution in the Bjorken limit and exhibits a sizeable
Q**2-dependence at lower Q**2, particular Q**2 is order of nu**2.Comment: 8 pages of LaTeX-text and 2 figure ps-file
Temperature dependence of nonlinear auto-oscillator linewidths: Application to spin-torque nano-oscillators
The temperature dependence of the generation linewidth for an auto-oscillator
with a nonlinear frequency shift is calculated. It is shown that the frequency
nonlinearity creates a finite correlation time, tau, for the phase
fluctuations. In the low-temperature limit in which the spectral linewidth is
smaller than 1/tau, the line shape is approximately Lorentzian and the
linewidth is linear in temperature. In the opposite high-temperature limit in
which the linewidth is larger than 1/tau, the nonlinearity leads to an apparent
"inhomogeneous broadening" of the line, which becomes Gaussian in shape and has
a square-root dependence on temperature. The results are illustrated for the
spin-torque nano-oscillator.Comment: 4 pages, 1 figur
Generation of spin-wave dark solitons with phase engineering
We generate experimentally spin-wave envelope dark solitons from rectangular
high-frequency dark input pulses with externally introduced phase shifts in
yttrium-iron garnet magnetic fims. We observe the generation of both odd and
even numbers of magnetic dark solitons when the external phase shift varies.
The experimental results are in a good qualitative agreement with the theory of
the dark-soliton generation in magnetic films developed earlier [Phys. Rev.
Lett. 82, 2583 (1999)].Comment: 6 pages, including 7 figures, submitted to Phys. Rev.
Kinetic-scale magnetic turbulence and finite Larmor radius effects at Mercury
We use a nonstationary generalization of the higher-order structure function
technique to investigate statistical properties of the magnetic field
fluctuations recorded by MESSENGER spacecraft during its first flyby
(01/14/2008) through the near Mercury's space environment, with the emphasis on
key boundary regions participating in the solar wind -- magnetosphere
interaction. Our analysis shows, for the first time, that kinetic-scale
fluctuations play a significant role in the Mercury's magnetosphere up to the
largest resolvable time scale ~20 s imposed by the signal nonstationarity,
suggesting that turbulence at this planet is largely controlled by finite
Larmor radius effects. In particular, we report the presence of a highly
turbulent and extended foreshock system filled with packets of ULF
oscillations, broad-band intermittent fluctuations in the magnetosheath,
ion-kinetic turbulence in the central plasma sheet of Mercury's magnetotail,
and kinetic-scale fluctuations in the inner current sheet encountered at the
outbound (dawn-side) magnetopause. Overall, our measurements indicate that the
Hermean magnetosphere, as well as the surrounding region, are strongly affected
by non-MHD effects introduced by finite sizes of cyclotron orbits of the
constituting ion species. Physical mechanisms of these effects and their
potentially critical impact on the structure and dynamics of Mercury's magnetic
field remain to be understood.Comment: 46 pages, 5 figures, 2 table
Cash is King: An Easy Way to Understand Debits and Credits
In Accounting, it is a well-known problem that many students often have difficulty in deciding whether to debit or credit an account to increase its balance. After practicing and teaching Accounting for more than forty years, the authors have developed a simple, practical and fault-proof method of handling debits and credits--the Cash is King method. Ten representative examples are provided to demonstrate how to use the Cash is King Method to assist the students handle debits and credits and guide them in recording all accounting transactions correctly
Power and linewidth of propagating and localized modes in nanocontact spin-torque oscillators
Integrated power and linewidth of a propagating and a self-localized spin
wave modes excited by spin-polarized current in an obliquely magnetized
magnetic nanocontact are studied experimentally as functions of the angle
between the external bias magnetic field and the nanocontact plane.
It is found that the power of the propagating mode monotonically increases with
, while the power of the self-localized mode has a broad maximum near
deg, and exponentially vanishes near the critical angle
deg, at which the localized mode disappears. The linewidth of
the propagating mode in the interval of angles deg, where only
this mode is excited, is adequtely described by the existing theory, while in
the angular interval where both modes can exist the observed linewidth of both
modes is substantially broadened due to the telegraph switching between the
modes. Numetical simulations and an approximate analytical model give good
semi-quantitative description of the observed results.Comment: 8 pages, 6 figure
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