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The recently released spacecraft potential measured by the RPW instrument on-board Solar Orbiter has been used to estimate the solar wind electron density in the inner heliosphere. Solar-wind electron density measured during June 2020 has…

The description of the turbulent spectrum of magnetic fluctuations in the solar wind in the kinetic range of scales is not yet completely established. Here, we perform a statistical study of 100 spectra measured by the STAFF instrument on…

太阳与恒星天体物理 · 物理学 2012-12-04 Olga Alexandrova , Catherine Lacombe , Andre Mangeney , Roland Grappin , Milan Maksimovic

The statistical properties of magnetic discontinuities in the solar wind are investigated by measuring fluctuations in the magnetic field direction, given by the rotation Delta theta that the magnetic field vector undergoes during time…

太阳与恒星天体物理 · 物理学 2015-06-11 Vladimir Zhdankin , Stanislav Boldyrev , Joanne Mason

Electron scale solar wind turbulence has attracted great interest in recent years. Clear evidences have been given from the Cluster data that turbulence is not fully dissipated near the proton scale but continues cascading down to the…

太阳与恒星天体物理 · 物理学 2015-06-15 F. Sahraoui , S. Y. Huang , J. De Patoul , G. Belmont , M. L. Goldstein , A. Retino , P. Robert , N. Cornilleau-Wehrlin

We analyze time series data of the fluctuations of slow solar wind velocity using rank order statistics. We selected a total of 18 datasets measured by the Helios spacecraft at a distance of 0.32 AU from the sun in the inner heliosphere.…

太阳与恒星天体物理 · 物理学 2011-12-23 Vinita Suyal , Awadhesh Prasad , Harinder P. Singh

For the past 30+ years, the magnetic expansion factor ($f_s$) has been used in empirical relationships to predict solar wind speed ($v_{obs}$) at 1 AU, based on an inverse relationship between these two quantities. Coronal unipolar…

太阳与恒星天体物理 · 物理学 2020-08-03 Samantha Wallace , Charles N. Arge , Nicholeen M. Viall , Ylva Pihlstrom

Fluctuations represent a major challenge for the incorporation of electric power from large wind-farms into power grids. Wind farm power output fluctuates strongly in time, over various time scales. Understanding these fluctuations,…

流体动力学 · 物理学 2014-12-24 Richard J. A. M. Stevens , Charles Meneveau

The solar wind speed at 1 AU shows variations in latitude and in time which reflect the evolution of the global background magnetic field during the activity cycle. It is commonly accepted that the terminal wind speed in a magnetic…

太阳与恒星天体物理 · 物理学 2016-07-27 R. F. Pinto , A. S. Brun , A. P. Rouillard

We present three-dimensional magnetic power spectra in wavevector space to investigate anisotropy and scalings of sub-Alfv\'enic solar wind turbulence at magnetohydrodynamic (MHD) scale using the Magnetospheric Multiscale spacecraft. The…

太阳与恒星天体物理 · 物理学 2022-11-29 S. Q. Zhao , Huirong Yan , Terry Z. Liu , Mingzhe Liu , Huizi Wang

The solar wind is a magnetized plasma and as such exhibits collective plasma behavior associated with its characteristic spatial and temporal scales. The characteristic length scales include the size of the heliosphere, the collisional mean…

空间物理 · 物理学 2020-01-01 Daniel Verscharen , Kristopher G. Klein , Bennett A. Maruca

The fluctuations in wind power entering an electrical grid (Irish grid) were analyzed and found to exhibit correlated fluctuations with a self-similar structure, a signature of large-scale correlations in atmospheric turbulence. The…

数据分析、统计与概率 · 物理学 2016-02-17 G. Bel , C. P. Connaughton , M. Toots , M. M. Bandi

A well-known property of solar wind plasma turbulence is the observed anisotropy of the autocorrelations, or equivalently the spectra, of velocity and magnetic field fluctuations. Here we explore the related but apparently not well-studied…

We present geomagnetic storms (GSs) selected from three solar cycles, spanning the years 1995 to 2022. We studied the development of the main phase of storms within disturbance storm time (Dst) amplitudes ranging from Dst =-64 nT to Dst=-…

太阳与恒星天体物理 · 物理学 2024-02-07 Osman M. Ahmed , Badruudin Zaheer Ahmad , Moncef Derouich

One of the key challenges in solar and heliospheric physics is to understand the acceleration of the solar wind. As a super-sonic, super-Alfv\'enic plasma flow, the solar wind carries mass, momentum, energy, and angular momentum from the…

太阳与恒星天体物理 · 物理学 2021-08-11 Daniel Verscharen , Stuart D. Bale , Marco Velli

Time series of photospheric magnetic parameters of solar active regions (ARs) are used to answer whether scaling properties of fluctuations embedded in such time series help to distinguish between flare-quiet and flaring ARs. We examine a…

太阳与恒星天体物理 · 物理学 2020-10-21 Eo-Jin Lee , Sung-Hong Park , Yong-Jae Moon

We first study the solar flare time sequence based on the GOES16 data. We find that the power spectrum density of the low-energy (E\leq E_{mean}) flare shows 1/f fluctuations, but the high-energy (E>E_{mean}) flare shows a flat spectrum.…

太阳与恒星天体物理 · 物理学 2023-10-12 Masahiro Morikawa , Akika Nakamichi

The original 110 year long 27-day Recurrence Index (original R27) was published more than forty years ago. That index, based on the autocorrelation of consecutive 27-day sets of the geomagnetic aa-index, is a measure of the cycle-to-cycle…

太阳与恒星天体物理 · 物理学 2021-01-07 H. H. Sargent

The nature of the magnetic field fluctuations in the solar wind between the ion and electron scales is still under debate. Using the Cluster/STAFF instrument, we make a survey of the power spectral density and of the polarization of these…

Solar Orbiter will observe the Sun and the inner heliosphere to study the connections between solar activity, coronal structure, and the origin of the solar wind. The plasma instruments on board Solar Orbiter will determine the…

空间物理 · 物理学 2020-01-08 Georgios Nicolaou , Daniel Verscharen , Robert T. Wicks , Christopher J. Owen

Large-scale compressive slow-mode-like fluctuations can cause variations in the density, temperature, and magnetic-field magnitude in the solar wind. In addition, they also lead to fluctuations in the differential flow $U_{\rm p\alpha}$…

空间物理 · 物理学 2023-08-07 Xingyu Zhu , Daniel Verscharen , Jiansen He , Bennett A. Maruca , Christopher J. Owen