相关论文: Statistical analysis and modeling of variations of…
The interplanetary magnetic field exhibits a distinctive $1/f$ spectral density from frequencies of around $\unit[10^{-6}]{Hz}$ to around $\unit[10^{-4}]{Hz}$, ranging from harmonics of the solar rotation to the reciprocal of the turbulence…
Fluctuations and structure across a wide range of spatial and temporal scales are frequently studied in the solar wind. The properties of the low-frequency fluctuations are of relevance to turbulent energy injection into the plasma and the…
The power spectrum of magnetic-field fluctuations in the fast solar wind ($V_{\rm SW}> 500 \mbox{ km} \mbox{ s}^{-1}$) at magnetohydrodynamic (MHD) scales is characterized by two different power laws on either side of a break frequency…
The record of reversals of the geomagnetic field has played an integral role in the development of plate tectonic theory. Statistical analyses of the reversal record are aimed at detailing patterns and linking those patterns to core-mantle…
We first report that the seismic time-sequence data from around the world, excluding major earthquakes, consistently yield the power spectral density inversely proportional to the frequency f. This is the 1/f fluctuation that appears…
Parker Solar Probe and Solar Orbiter data are used to investigate the radial evolution of magnetic turbulence between $0.06 ~ \lesssim R ~\lesssim 1$ au. The spectrum is studied as a function of scale, normalized to the ion inertial scale…
Field reversals are the most spectacular changes in the geomagnetic field but remain little understood. Paleomagnetic data primarily constrain the reversal rate and provide few additional clues. Reversals and excursions are characterized by…
Employing a simple ideal magnetohydrodynamic model in spherical geometry,we show that the presence of either rotation or finite magnetic helicity is sufficient to induce dynamical reversals of the magnetic dipole moment. The statistical…
In the present paper, we investigate the power-law behaviour of the magnetic field spectra in the Earths magnetosheath region using Cluster spacecraft data under solar minimum condition. The power spectral density of the magnetic field data…
The power spectrum of the evolving solar wind shows evidence of a spectral break between an inertial range of turbulent fluctuations at higher frequencies and a "$1/f$" like region at lower frequencies. In the ecliptic plane at $\sim 1$ AU,…
The geomagnetic field has undergone hundreds of polarity reversals over Earth's history, at a variable pace. In numerical models of Earth's core dynamics, reversals occur with increasing frequency when the convective forcing is increased…
The trace magnetic power spectrum in the solar wind is known to be characterized by a double power law at scales much larger than the proton gyro-radius, with flatter spectral exponents close to -1 found at the lower frequencies below an…
Using a spherical symmetric mean field alpha^2-dynamo model for Earth's magnetic field reversals, we show the coexistence of the noise-induced phenomena coherence resonance and stochastic resonance. Stochastic resonance has been recently…
A parametric study of the magnetic dipole behavior in resistive incompressible MHD inside a rotating sphere is performed, using direct numerical simulations and considering Reynolds and Ekman numbers as controlling parameters. The tendency…
Observations show that the photospheric solar magnetic dipole usually does not vanish during the reversal of the solar magnetic field, which occurs in each solar cycle. In contrast, mean-field solar dynamo models predict that the dipole…
We present a mechanism for the formation of the low frequency 1/f magnetic spectrum based on numerical solutions of a shell reduced-MHD model of the turbulent dynamics inside the sub-Alfv\'enic solar wind. We assign reasonably realistic…
Recent Fourier analyses of fossil extinction data have indicated that the power spectrum of extinction during the Phanerozoic may take the form of 1/f noise, a result which, it has been suggested, could be indicative of the presence of…
The turbulent spectrum of magnetic fluctuations in the solar wind displays a spectral break at ion characteristic scales. At electron scales the spectral shape is not yet completely established. Here, we perform a statistical study of 102…
The asymmetric shape of reversals of the Earth's magnetic field indicates a possible connection with relaxation oscillations as they were early discussed by van der Pol. A simple mean-field dynamo model with a spherically symmetric $\alpha$…
The redshifted cosmic 21 cm line signal of neutral hydrogen provides the possibility to constrain the matter power spectrum. Cross correlating temperature maps at different frequencies (corresponding to different redshifts along the line of…