We perform 2.5D hybrid simulations with massless fluid electrons and kinetic particle-in-cell ions to study the temporal evolution of ion temperatures, temperature anisotropies and velocity ...distribution functions in relation to the dissipation and turbulent evolution of a broad-band spectrum of parallel and obliquely propagating Alfvén-cyclotron waves. The purpose of this paper is to study the relative role of parallel versus oblique Alfvén-cyclotron waves in the observed heating and acceleration of minor ions in the fast solar wind. We consider collisionless homogeneous multi-species plasma, consisting of isothermal electrons, isotropic protons and a minor component of drifting \(\alpha\) particles in a finite-\(\beta\) fast stream near the Earth. The kinetic ions are modeled by initially isotropic Maxwellian velocity distribution functions, which develop non-thermal features and temperature anisotropies when a broad-band spectrum of low-frequency non-resonant, \(\omega \leq 0.34 \Omega_p\), Alfvén-cyclotron waves is imposed at the beginning of the simulations. The initial plasma parameter values, such as ion density, temperatures and relative drift speeds, are supplied by fast solar wind observations made by the \textit{Wind} spacecraft at 1AU. The imposed broad-band wave spectra is left-hand polarized and resembles \textit{Wind} measurements of Alfvénic turbulence in the solar wind. The imposed magnetic field fluctuations for all cases are within the inertial range of the solar wind turbulence and have a Kraichnan-type spectral slope \(\alpha=-3/2\). We vary the propagation angle from \(\theta= 0^\circ\) to \(\theta=30^\circ\) and \(\theta=60^\circ\), and find that the minor ion heating is most efficient for the highly-oblique waves propagating at \(60^\circ\), whereas the protons exhibit perpendicular cooling at all propagation angles.
Heating of magnetized turbulent plasma is calculated in the framework of
Burgers turbulence A.M. Polyakov, Phys. Rev. E. 52, 6183 (1995). Explicit
formula for the energy flux of Alfven waves along ...the magnetic field is
presented. The Alfven waves are considered as intermediary between the
turbulent energy and the heat. The derived results are related to a wave
channel of heating of the solar corona. If we incorporate amplification of
Alfven waves by shear flow the suggested model of heating can be applied to
analysis of the missing viscosity of accretion discs and to reveal why the
quasars are the most powerful sources of light in the universe. We suppose that
the Langevin-Burgers approach to turbulence we have applied in the current work
can be also helpful for other systems where we have intensive interaction
between a stochastic turbulent system and waves and can be used in many
multidisciplinary researches in hydrodynamics and MHD.
The differential conductivity for the out-of-plane transport in layered
cuprates is calculated for Lawrence-Doniach model in the framework of
time-dependent Ginzburg-Landau (TDGL) theory. The TDGL ...equation for the
superconducting order parameter is solved in the presence of Langevin external
noise, describing the birth of fluctuation Cooper pairs. The TDGL correlator of
the superconducting order parameter is calculated in momentum representation
and it is shown that the so defined number of particles obeys the Boltzmann
equation. The fluctuation conductivity is given by an integral over the
Josephson phase \theta of the particles distribution, depending on that phase,
n(\theta) and their velocity v(\theta). It is demonstrated that in case of
overcooling under T_c the transition from normal to superconducting phase while
reducing the external electric field runs via annulation of the differential
conductivity. The presented results can be used for analysis and experimental
data processing of measurements of differential conductivity and fluctuation
current in strong electric and magnetic fields. The possible usage of a
negative differential conductivity (NDC) for generation of THz oscillations is
shortly discussed.
Eur.Phys.J.D44:533-536,2007 Absorbtion of Alfven waves is considered to be the main mechanism of heating
in the solar corona. It is concluded that the sharp increase of the plasma
temperature by two ...orders of magnitude is related to a self-induced opacity
with respect to Alfven waves. The maximal frequency for propagation of Alfven
waves is determined by the strongly temperature dependent kinematic viscosity.
In such a way the temperature jump is due to absorption of high frequency
Alfven waves in a narrow layer above the solar surface. It is calculated that
the power per unit area dissipated in this layer due to damping of Alfven waves
blows up the plasma and gives birth to the solar wind. A model short
wave-length (WKB) evaluation takes into account the 1/f^2 frequency dependance
of the transversal magnetic field and velocity spectral densities. Such
spectral densities agree with old magnetometric data taken by Voyager 1 and
recent theoretical calculations in the framework of Langevin-Burgers MHD. The
present theory predicts existence of intensive high frequency MHD Alfven waves
in the cold layer beneath the corona. It is briefly discussed how this
statement can be checked experimentally. It is demonstrated that the magnitude
of the Alfven waves generating random noise and the solar wind velocity can be
expressed only in terms of satellite experimental data. It is advocated that
investigation of properties of the solar surface as a random driver by optical
methods is an important task for future solar physics. Jets of accretion disks
are speculated as a special case of the wind from magnetized turbulent plasma.
The heating of magnetized plasma by propagation of Alfven waves is calculated
as a function of the magnetic field spectral density. The results can be
applied to evaluate the heating power of the ...solar corona at known data from
satellites' magnetometers. This heating rate can be incorporated in global
models for heating of the solar corona and creation of the solar wind. The
final formula for the heating power is illustrated with a model spectral
density of the magnetic field obtained by analysis of the Voyager 1 mission
results. The influence of high frequency dissipative modes is also taken into
account and it is concluded that for evaluation of the total coronal heating it
is necessary to know the spectral density of the fluctuating component of the
magnetic field up to the frequency of electron-proton collisions.
The differential conductivity for the out-of-plane transport in layered cuprates is calculated for Lawrence-Doniach model in the framework of time-dependent Ginzburg-Landau (TDGL) theory. The TDGL ...equation for the superconducting order parameter is solved in the presence of Langevin external noise, describing the birth of fluctuation Cooper pairs. The TDGL correlator of the superconducting order parameter is calculated in momentum representation and it is shown that the so defined number of particles obeys the Boltzmann equation. The fluctuation conductivity is given by an integral over the Josephson phase \theta of the particles distribution, depending on that phase, n(\theta) and their velocity v(\theta). It is demonstrated that in case of overcooling under T_c the transition from normal to superconducting phase while reducing the external electric field runs via annulation of the differential conductivity. The presented results can be used for analysis and experimental data processing of measurements of differential conductivity and fluctuation current in strong electric and magnetic fields. The possible usage of a negative differential conductivity (NDC) for generation of THz oscillations is shortly discussed.
Heating of magnetized turbulent plasma is calculated in the framework of Burgers turbulence A.M. Polyakov, Phys. Rev. E. 52, 6183 (1995). Explicit formula for the energy flux of Alfven waves along ...the magnetic field is presented. The Alfven waves are considered as intermediary between the turbulent energy and the heat. The derived results are related to a wave channel of heating of the solar corona. If we incorporate amplification of Alfven waves by shear flow the suggested model of heating can be applied to analysis of the missing viscosity of accretion discs and to reveal why the quasars are the most powerful sources of light in the universe. We suppose that the Langevin-Burgers approach to turbulence we have applied in the current work can be also helpful for other systems where we have intensive interaction between a stochastic turbulent system and waves and can be used in many multidisciplinary researches in hydrodynamics and MHD.
Absorbtion of Alfven waves is considered to be the main mechanism of heating in the solar corona. It is concluded that the sharp increase of the plasma temperature by two orders of magnitude is ...related to a self-induced opacity with respect to Alfven waves. The maximal frequency for propagation of Alfven waves is determined by the strongly temperature dependent kinematic viscosity. In such a way the temperature jump is due to absorption of high frequency Alfven waves in a narrow layer above the solar surface. It is calculated that the power per unit area dissipated in this layer due to damping of Alfven waves blows up the plasma and gives birth to the solar wind. A model short wave-length (WKB) evaluation takes into account the 1/f^2 frequency dependance of the transversal magnetic field and velocity spectral densities. Such spectral densities agree with old magnetometric data taken by Voyager 1 and recent theoretical calculations in the framework of Langevin-Burgers MHD. The present theory predicts existence of intensive high frequency MHD Alfven waves in the cold layer beneath the corona. It is briefly discussed how this statement can be checked experimentally. It is demonstrated that the magnitude of the Alfven waves generating random noise and the solar wind velocity can be expressed only in terms of satellite experimental data. It is advocated that investigation of properties of the solar surface as a random driver by optical methods is an important task for future solar physics. Jets of accretion disks are speculated as a special case of the wind from magnetized turbulent plasma.
The heating of magnetized plasma by propagation of Alfven waves is calculated as a function of the magnetic field spectral density. The results can be applied to evaluate the heating power of the ...solar corona at known data from satellites' magnetometers. This heating rate can be incorporated in global models for heating of the solar corona and creation of the solar wind. The final formula for the heating power is illustrated with a model spectral density of the magnetic field obtained by analysis of the Voyager 1 mission results. The influence of high frequency dissipative modes is also taken into account and it is concluded that for evaluation of the total coronal heating it is necessary to know the spectral density of the fluctuating component of the magnetic field up to the frequency of electron-proton collisions.
The set of equations for magnetohydrodynamic (MHD) waves in a shear flow is
consecutively derived. The proposed scenario involves the presence of a
self-sustained turbulence and magnetic field. In ...the framework of
Langevin--Burgers approach the influence of the turbulence is described by an
additional external random force in the MHD system. Kinetic equation for the
spectral density of the slow magnetosonic (Alfvenic) mode is derived in the
short wavelength (WKB) approximation. The results show a pressing need for
conduction of numerical Monte Carlo (MC) simulations with a random driver to
take into account the influence of the long wavelength modes and to give a more
precise analytical assessment of the short ones. Realistic MC calculations for
the heating rate and shear stress tensor should give an answer to the
perplexing problem for the missing viscosity in accretion disks and reveal why
the quasars are the most powerful sources of light in the universe. The planned
MC calculations can be incorporated in global models for accretion disks and
also in all other physical conditions where there is a shear flow in a
magnetized turbulent plasma. It is supposed that the heating mechanism by
Alfven waves absorption is common for many kinds of space plasmas from solar
corona to active galactic nuclei and the solution of these longstanding puzzles
deserves active interdisciplinary research. The work is illustrated by
numerical calculations and by exact solutions for the time dependence of the
magnetic field given by the Heun function.
