Origin of long - period Alfvén waves in the solar wind
نویسندگان
چکیده
We suggest that the observed long-period Alfvén waves in the solar wind may be generated in the solar interior due to the pulsation of the Sun in the fundamental radial mode. The period of this pulsation is about 1 hour. The pulsation causes a periodical variation of density and large-scale magnetic field, this affecting the Alfvén speed in the solar interior. Consequently the Alfvén waves with the half frequency of pulsation (i.e. with the double period) can be parametrically amplified in the interior below the convection zone due to the recently suggested swing wave-wave interaction. Therefore the amplified Alfvén waves have periods of several hours. The waves can propagate upwards through the convection zone to the solar atmosphere and cause the observed long-period Alfvén oscillations in the solar wind.
منابع مشابه
Generation of Alfvén Waves by Small-Scale Magnetic Reconnection in Solar Spicules
Alfvén waves dissipation is an extensively studied mechanism for the coronal heating problem. These waves can be generated by magnetic reconnection and propagated along the reconnected field lines. Here, we study the generation of Alfvén waves at the presence of both steady flow and sheared magnetic field in the longitudinally density stratified of solar spicules. The initial flow is assumed to...
متن کاملIonospheric cusp flows pulsed by solar wind Alfvén waves
Pulsed ionospheric flows (PIFs) in the cusp footprint have been observed by the SuperDARN radars with periods between a few minutes and several tens of minutes. PIFs are believed to be a consequence of the interplanetary magnetic field (IMF) reconnection with the magnetospheric magnetic field on the dayside magnetopause, ionospheric signatures of flux transfer events (FTEs). The quasiperiodic P...
متن کاملCoronal heating and wind acceleration by nonlinear Alfvén waves – global simulations with gravity, radiation, and conduction
We review our recent results of global onedimensional (1-D) MHD simulations for the acceleration of solar and stellar winds. We impose transverse photospheric motions corresponding to the granulations, which generate outgoing Alfvén waves. We treat the propagation and dissipation of the Alfvén waves and consequent heating from the photosphere by dynamical simulations in a self-consistent manner...
متن کاملAlfvén waves as a solar-interplanetary driver of the thermospheric disturbances
Alfvén waves have been proposed as an important mechanism for the heating of the Sun's outer atmosphere and the acceleration of solar wind, but they are generally believed to have no significant impact on the Earth's upper atmosphere under quiet geomagnetic conditions due to their highly fluctuating nature of interplanetary magnetic field (i.e., intermittent southward magnetic field component)....
متن کاملConstraining Low-frequency Alfvénic Turbulence in the Solar Wind Using Density Fluctuation Measurements
One proposed mechanism for heating the solar wind, from close to the sun to beyond ∼ 10 AU, invokes lowfrequency, oblique, Alfvén-wave turbulence. Because small-scale oblique Alfvén waves (kinetic Alfvén waves) are compressive, the measured density fluctuations in the solar wind place an upper limit on the amplitude of kinetic Alfvén waves and hence an upper limit on the rate at which the solar...
متن کامل