Search Publications
A study on the solar coronal dynamics during the post-maxima phase of the solar cycle 24 using S-band radio signals from the Indian Mars Orbiter Mission
Jain, Richa N.; Choudhary, R. K.; Bhardwaj, Anil +3 more
Radio signals from India's Mars Orbiter Mission (MOM) have been used to study turbulence in the solar plasma during the post-maximum phase of solar cycle 24. S-band (2.29 GHz) radio carrier downlink signals from MOM were received at the Indian Deep Space Network, Bangalore, and frequency residuals were spectrally analysed to obtain coronal turbule…
Dissipation of hydromagnetic waves in the viscous polytropic zone of the solar wind including FLR corrections, ohmic diffusion, and the Hall effect
Fok, Mei-Ching; Desta, Ephrem Tesfaye; Prajapati, Ram Prasad +1 more
In the polytropic zone of the solar wind, we have used the generalized polytrope pressure laws to investigate the dissipation of hydromagnetic waves and pressure-anisotropy-driven fluid instabilities in magnetized viscous plasmas, including finite Larmor radius (FLR) corrections and non-ideal magnetohydrodynamic (MHD) effects. The modified dispers…
Flux conservation, radial scalings, Mach numbers, and critical distances in the solar wind: magnetohydrodynamics and Ulysses observations
Verscharen, Daniel; Velli, Marco; Bale, Stuart D.
One of the key challenges in solar and heliospheric physics is to understand the acceleration of the solar wind. As a super-sonic, super-Alfvénic plasma flow, the solar wind carries mass, momentum, energy, and angular momentum from the Sun into interplanetary space. We present a framework based on two-fluid magnetohydrodynamics to estimate the flu…
Solar wind temperature-velocity relationship over the last five solar cycles and Forbush decreases associated with different types of interplanetary disturbance
Melkumyan, A. A.; Belov, A. V.; Abunina, M. A. +4 more
The behaviour of the solar wind (SW) proton temperature and velocity and their relationship during Forbush decreases (FDs) associated with various types of solar source - coronal mass ejections (CMEs) and coronal holes (CHs) - have been studied. Analysis of cosmic ray variations, SW temperature, velocity, density, plasma beta, and magnetic field (…
Searching for gravitational waves via Doppler tracking by future missions to Uranus and Neptune
Saha, Prasenjit; D'Orazio, Daniel J.; Soyuer, Deniz +1 more
The past year has seen numerous publications underlining the importance of a space mission to the ice giants in the upcoming decade. Proposed mission plans involve a ∼10 yr cruise time to the ice giants. This cruise time can be utilized to search for low-frequency gravitational waves (GWs) by observing the Doppler shift caused by them in the Earth…
Generalized anisotropic κ-cookbook: 2D fitting of Ulysses electron data
Fichtner, H.; Scherer, K.; Lazar, M. +1 more
Observations in space plasmas reveal particle velocity distributions out of thermal equilibrium, with anisotropies (e.g. parallel drifts and/or different temperatures, T∥ - parallel and T⊥ - perpendicular, with respect to the background magnetic field), and multiple quasi-thermal and suprathermal populations with different pr…
Charge-exchange soft X-ray emission of highly charged ions with inclusion of multiple-electron capture
Cui, W.; Zhao, G.; Wu, Y. +7 more
Charge exchange has been recognized as a primary source of soft X-ray emission in many astrophysical outflow environments, including cometary and planetary exospheres impacted by the solar wind. Some models have been set up by using different data collections of charge-exchange cross-sections. However, multiple-electron transfer has not been inclu…
The κ-cookbook: a novel generalizing approach to unify κ-like distributions for plasma particle modelling
Fichtner, H.; Scherer, K.; Lazar, M. +1 more
In the literature different so-called κ-distribution functions are discussed to fit and model the velocity (or energy) distributions of solar wind species, pickup ions, or magnetospheric particles. Here, we introduce a generalized (isotropic) κ-distribution as a 'cookbook', which admits as special cases, or 'recipes', all the other known versions …
Characteristics of solar wind rotation
Li, K. J.; Feng, W.
Over 54 yr of hourly mean value of solar wind velocity from 1963 November 27 to 2017 December 31 are used to investigate characteristics of the rotation period of solar wind through autocorrelation analysis. Solar wind of high velocity is found to rotate faster than low-velocity wind, while its rotation rate increases with increasing velocity, but…
Kinetic Theory and Fast Wind Observations of the Electron Strahl
Wilson, Lynn B., III; Horaites, Konstantinos; Viñas, Adolfo F. +2 more
We develop a model for the strahl population in the solar wind - a narrow, low-density and high-energy electron beam centred on the magnetic field direction. Our model is based on the solution of the electron drift-kinetic equation at heliospheric distances where the plasma density, temperature and the magnetic field strength decline as power laws…