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Related papers: On the estimation of solar wind velocity under var…

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Using data collected by the Indian Mars Orbiter Mission in October 2021, we investigated coronal regions of the Sun by analyzing the Doppler spectral width of radio signals to estimate solar wind velocity. A simplified equation is…

Solar and Stellar Astrophysics · Physics 2025-04-02 Keshav Aggarwal , R. K. Choudhary , Abhirup Datta , Roopa M. V. , Bijoy K. Dai

We present a turbulence index independent framework for simultaneously deriving solar wind velocity and coronal electron density in the near-Sun region using the spectral broadening of spacecraft radio signals. The formulation accommodates…

Solar and Stellar Astrophysics · Physics 2026-03-25 Keshav Aggarwal , R. K. Choudhary , Abhirup Datta , Soumyaneal Banerjee , Takeshi Imamura , Hiroki Ando

We present a unified method to derive both solar wind velocities and coronal electron densities in the near-Sun corona using Doppler spectral broadening of spacecraft radio signals. The method is generalized to be frequency independent…

Solar and Stellar Astrophysics · Physics 2026-03-26 Keshav Aggarwal , R. K. Choudhary , Abhirup Datta , Roopa M. V. , Takeshi Imamura , Hiroki Ando

The solar inner corona is a region that plays a critical role in energizing the solar wind and propelling it to supersonic and supra-Alfvenic velocities. Despite its importance, this region remains poorly understood because of being least…

Solar and Stellar Astrophysics · Physics 2023-08-25 Richa N. Jain , R. K. Choudhary , Anil Bhardwaj , T. Imamura , Anshuman Sharma , Umang M. Parikh

Recent in-situ observations and numerical models indicated various types of magnetohydrodynamic (MHD) waves contributing to the solar wind acceleration. Among them is an MHD wave decomposition at distances closer than 50 $R_{\odot}$ using…

Solar and Stellar Astrophysics · Physics 2025-03-19 Shota Chiba , Munehito Shoda , Takeshi Imamura

This paper presents the analysis of 3D evolution of solar wind density turbulence and speed at various levels of solar activity between solar cycles 22 and 24. The solar wind data has been obtained from interplanetary scintillation (IPS)…

Solar and Stellar Astrophysics · Physics 2015-06-04 P. K. Manoharan

We utilize observations from the Parker Solar Probe (PSP) to study the radial evolution of the solar wind in the inner heliosphere. We analyze electron velocity distribution functions observed by the Solar Wind Electrons, Alphas, and…

We present measurements of the wind speeds at the nightside lower clouds of Venus from observations by JAXA's mission Akatsuki during 2016, complemented with new wind measurements from ground-based observations acquired with TNG/NICS in…

We analyze in situ measurements of solar wind velocity obtained by the Advanced Composition Explorer (ACE) spacecraft during the solar activity cycle 23. We calculated a robust complexity measure, the permutation entropy (S) of solar wind…

Solar and Stellar Astrophysics · Physics 2011-12-23 Vinita Suyal , Awadhesh Prasad , Harinder P. Singh

We present in this Letter the first coordinated radio occultation measurements and ultraviolet observations of the inner corona below 5.5 Rs, obtained during the Galileo solar conjunction in January 1997, to establish the origin of the slow…

Astrophysics · Physics 2009-10-30 S. R. Habbal , R. Woo , S. Fineschi , R. O'Neal , J. Kohl , G. Noci , C. Korendyke

(Abridged) Wavelet analysis can be used to measure the power spectrum of solar wind fluctuations along a line in any direction with respect to the local mean magnetic field. This technique is applied to study solar wind turbulence in…

Earth and Planetary Astrophysics · Physics 2011-02-11 J. J. Podesta

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.…

Solar and Stellar Astrophysics · Physics 2011-12-23 Vinita Suyal , Awadhesh Prasad , Harinder P. Singh

An empirical model for forecasting solar wind speed related geomagnetic events is presented here. The model is based on the estimated location and size of solar coronal holes. This method differs from models that are based on photospheric…

Astrophysics · Physics 2008-11-26 S. Robbins , C. J. Henney , J. W. Harvey

Observation of Interplanetary Scintillation (IPS) provides an important and effective way to study the solar wind and the space weather. A series of IPS observations were conducted by the Five-hundred-meter Aperture Spherical radio…

Solar and Stellar Astrophysics · Physics 2022-08-03 Li-Jia Liu , Bo Peng , Lei Yu , Bin Liu , Ji-Guang Lu , Ye-Zhao Yu , Hong-Wei Xi , Ming Xiong , O. Chang

We present a method to derive outflow velocities in the solar corona using different data sets including solar wind mass flux coming from the SWAN/SOHO instrument, electron density values from LASCO-C2 and interplanetary solar wind…

Astrophysics · Physics 2009-11-13 E. Quemerais , R. Lallement , D. Koutroumpa , P. Lamy

During the first superior conjunction of the Tianwen-1 Mars probe in October 2021, its downlink signal received by the Wuqing 70-m radio telescope passed within 4.53 solar radii of the Sun. The signal was significantly perturbed by the…

Solar and Stellar Astrophysics · Physics 2026-04-16 Yu-Chen Liu , De-Qing Kong , Song Tan , Zi-Han Zhao , Zan Wang , Dong-Hao Liu , Xin-Ying Zhu , Yan Su , Hong-Bo Zhang

Variations in the solar wind density introduce variable delays into pulsar timing observations. Current pulsar timing analysis programs only implement simple models of the solar wind, which not only limit the timing accuracy, but can also…

Astrophysics · Physics 2009-11-13 X. P. You , G. B. Hobbs , W. A. Coles , R. N. Manchester , J. L. Han

Waves are thought to play a significant role in the heating of the solar atmosphere and the acceleration of the wind. Among the many types of waves observed in the Sun, the so-called p-modes with a 3 mHz frequency peak dominate the lower…

The properties of the solar wind, as measured in situ throughout the heliosphere, depend both on the characteristics of its coronal source and on the intrinsic processes governing its interplanetary evolution. Recently, radial and Parker…

In this paper, we analyze the probability density function (PDF) of solar wind velocity and proton density, based on generalized thermostatistics (GT) approach, comparing theoretical results with observational data. The time series analyzed…

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