scholarly journals Background for gravitational wave signal at LISA from refractive index of solar wind plasma

2020 ◽  
Vol 499 (1) ◽  
pp. L77-L81
Author(s):  
Adam Smetana

ABSTRACT A strong indication is presented that the space-based gravitational antennas, in particular the Laser Interferometer Space Antenna (LISA) concept introduced in 2017 in response to the ESA call for L3 mission concepts, are going to be sensitive to a strong background signal interfering with the prospected signal of gravitational waves. The false signal is due to variations in the electron number density of the solar wind, causing variations in the refractive index of plasma flowing through interplanetary space. As countermeasures, two solutions are proposed. The first solution is to deploy enough solar wind detectors to the LISA mission to allow for reliable knowledge of the solar wind background. The second solution is to equip the LISA interferometer with a second laser beam with a distinct wavelength to allow cancelling of the background solar wind signal from the interferometric data.

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Kazuo Shiokawa ◽  
Katya Georgieva

AbstractThe Sun is a variable active-dynamo star, emitting radiation in all wavelengths and solar-wind plasma to the interplanetary space. The Earth is immersed in this radiation and solar wind, showing various responses in geospace and atmosphere. This Sun–Earth connection variates in time scales from milli-seconds to millennia and beyond. The solar activity, which has a ~11-year periodicity, is gradually declining in recent three solar cycles, suggesting a possibility of a grand minimum in near future. VarSITI—variability of the Sun and its terrestrial impact—was the 5-year program of the scientific committee on solar-terrestrial physics (SCOSTEP) in 2014–2018, focusing on this variability of the Sun and its consequences on the Earth. This paper reviews some background of SCOSTEP and its past programs, achievements of the 5-year VarSITI program, and remaining outstanding questions after VarSITI.


2021 ◽  
Author(s):  
Daniele Telloni ◽  

<p>Radial alignments between pairs of spacecraft is the only way to observationally investigate the turbulent evolution of the solar wind as it expands throughout interplanetary space. On September 2020 Parker Solar Probe (PSP) and Solar Orbiter (SolO) were nearly perfectly radially aligned, with PSP orbiting around its perihelion at 0.1 au (and crossing the nominal Alfvén point) and SolO at 1 au. PSP/SolO joint observations of the same solar wind plasma allow the extraordinary and unprecedented opportunity to study how the turbulence properties of the solar wind evolve in the inner heliosphere over the wide distance of 0.9 au. The radial evolution of (i) the MHD properties (such as radial dependence of low- and high-frequency breaks, compressibility, Alfvénic content of the fluctuations), (ii) the polarization status, (iii) the presence of wave modes at kinetic scale as well as their distribution in the plasma instability-temperature anisotropy plane are just few instances of what can be addressed. Of furthest interest is the study of whether and how the cascade transfer and dissipation rates evolve with the solar distance, since this has great impact on the fundamental plasma physical processes related to the heating of the solar wind. In this talk I will present some of the results obtained by exploiting the PSP/SolO alignment data.</p>


Author(s):  
P.I. Vysikaylo ◽  
N.S. Ryabukha

Interference of gravitational and Coulomb potentials in the entire heliosphere is considered, it is being manifested in generation of two opposite flows of charged particles: 1) that are neutral or with a small charge to the Sun, and 2) in the form of a solar wind from the Sun. According to the Einstein --- Smoluchowski relation Te(R) = eDe / µe ~ (E/N)0.75 based on the N experimental values (heavy particles number density --- the ne electron concentration), the Te electron temperature in the entire heliosphere was for the first time analytically calculated depending on the charge of the Sun and distance to it R. Calculated values of the registered ion parameters in the solar wind were compared with experimental observations. Reasons for generating the ring current in inhomogeneous heliosphere and inapplicability of the Debye theory in describing processes in the solar wind (plasma with current) are considered


2002 ◽  
Vol 199 ◽  
pp. 426-429 ◽  
Author(s):  
P.K. Manoharan ◽  
M. Pick ◽  
Lasco Consortium

When radio waves propagate through a irregular medium, scattering by the random refractive index inhomogeneities can lead to a wide variety of phenomena, which include intensity scintillation. The observed scattering can be interpreted to gain information about the random medium and such inversion studies are valuable when the accessibility of the medium becomes difficult. This paper briefly describes the intensity scintillation of celestial radio sources caused by the turbulence in the solar wind and summarizes the salient features of the method employed in mapping the structure of disturbances leaving the Sun out to ∼1 AU.


2002 ◽  
Vol 12 ◽  
pp. 398
Author(s):  
X.Z. Zhang ◽  
J.H. Wu

The radio wave from distant radio sources will be scattered by the irregular structures of the solar wind plasma when propagating through the interplanetary space, resulting into a randomly fluctuating pattern of the radio wave in observation. This pattern is called interplanetary scintillation (IPS). Observation on IPS can give information of the solar wind speed and irregular structures in solar wind plasma. The IPS observations began at Miyun Station, Beijing Astronomical Observatory from the late half of 1999. The properties of the telescope and description of the data analysis can be found in the papers of Wang (1987) and Wu, Zhang and Zheng (2000) respectively.Table 1 summarizes some observational results using IPS source 3C48 in April and May 2000. The Fresnel knees and the first minima in the IPS spectra were used to estimate solar wind speeds. Comparisons of our results with the unpublished data of Hiraiso Solar Terrestrial Research Center obtained from their web site, have been done and good agreement between the two systems was found. Since the collecting area of Miyun telescope is limited, the system noise is relatively high and dominates the high-frequency parts of the spectra. The Miyun IPS observation and data reduction procedures are still under developing and will soon be completed.


2003 ◽  
Vol 21 (6) ◽  
pp. 1341-1345 ◽  
Author(s):  
G. Exarhos ◽  
X. Moussas

Abstract. We study the dependence of cosmic rays with heliolatitude using a simple method and compare the results with the actual data from Ulysses and IMP spacecraft. We reproduce the galactic cosmic-ray heliographic latitudinal intensity variations, applying a semi-empirical, 2-D diffusion-convection model for the cosmic-ray transport in the interplanetary space. This model is a modification of our previous 1-D model (Exarhos and Moussas, 2001) and includes not only the radial diffusion of the cosmic-ray particles but also the latitudinal diffusion. Dividing the interplanetary region into "spherical magnetic sectors" (a small heliolatitudinal extension of a spherical magnetized solar wind plasma shell) that travel into the interplanetary space at the solar wind velocity, we calculate the cosmic-ray intensity for different heliographic latitudes as a series of successive intensity drops that all these "spherical magnetic sectors" between the Sun and the heliospheric termination shock cause the unmodulated galactic cosmic-ray intensity. Our results are compared with the Ulysses cosmic-ray measurements obtained during the first pole-to-pole passage from mid-1994 to mid-1995.Key words. Interplanetary physics (cosmic rays; interplanetray magnetic fields; solar wind plasma)


2020 ◽  
Vol 220 ◽  
pp. 01090
Author(s):  
N. A. Barkhatov ◽  
S.E. Revunov ◽  
O. T. Cherney ◽  
Zh. V. Smirnova ◽  
M. V. Mukhina

Comparison of wavelet spectrum (skeletons) local maxima for disturbed components of solar plasma flow parameters and geomagnetic field disturbances recorded along the meridional station chain during geomagnetic storm intervals is performed in the range of magnetohydrodynamic (MHD) waves. An algorithm for quantitative evaluation of analyzed skeletons consistency has been developed. It has been used to demonstrate the possibility of the type of solar wind plasma flow elaboration on unique spectral signs of Solar wind speed disturbances, density and interplanetary magnetic field. It is shown that the energy spectrum of oscillations for these parameters reflects the internal structure of the corresponding plasma formation. The skeletons application to the analysis of the interplanetary space main parameters made it possible to estimate the magnetosphere reaction time in geomagnetic field horizontal component oscillations at different latitudes on the disturbance. As a result, the distributed magnetosphere reaction over latitude was determined in the form of geomagnetic field oscillations on the disturbed solar flow parameters. It is shown that the dynamics of the components of the solar wind parameters disturbance spectra corresponding to plasma flows manifest themselves in the MHD spectra of high-latitude stations magnetograms and can be used as a diagnostic tool.


2018 ◽  
Vol 7 (4.38) ◽  
pp. 1078
Author(s):  
N. A. Barkhatov ◽  
S. E. Revunov ◽  
O. M. Barkhatova ◽  
E. A. Revunova ◽  
D. S. Dolgova ◽  
...  

Comparison of wavelet spectrum (skeletons) local maxima for disturbed components of solar plasma flow parameters and geomagnetic field disturbances recorded along the meridional station chain during geomagnetic storm intervals is performed in the range of magnetohydrodynamic (MHD) waves. An algorithm for quantitative evaluation of analyzed skeletons consistency has been developed. It has been used to demonstrate the possibility of the type of solar wind plasma flow elaboration on unique spectral signs of Solar wind speed disturbances, density and interplanetary magnetic field. It is shown that the energy spectrum of oscillations for these parameters reflects the internal structure of the corresponding plasma formation. The skeletons application to the analysis of the interplanetary space main parameters made it possible to estimate the magnetosphere reaction time in geomagnetic field horizontal component oscillations at different latitudes on the disturbance. As a result, the distributed magnetosphere reaction over latitude was determined in the form of geomagnetic field oscillations on the disturbed solar flow parameters. It is shown that the dynamics of the components of the solar wind parameters disturbance spectra corresponding to plasma flows manifest themselves in the MHD spectra of high-latitude stations magnetograms and can be used as a diagnostic tool.  


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