Correlability of solar wind with seismic events in the Balkan peninsula zone

The Solar Heliospheric Observatory (SOHO) satellite was launched on the 2nd of December 1995 at L1 Lagrange point (1.5x106 km from Earth) with the purpose of gathering data for helioseismology, remote sensing of the solar atmosphere, and solar wind in situ. The satellite was positioned into orbit in early 1996, with data acquisition expected to commence on January 20th. The correlation between increased values of solar wind parameters and earthquakes in the Balkan peninsula zone between 1996 and 2018 was made possible by data obtained through continuous proton density and proton velocity monitoring. The assessment of the anomalous threshold was based on statistically determined parameters due to the huge fluctuation of solar wind over time and distinct value increases of proton density and speed. Visual representations of proton density and proton speed were created for the time window preceding each earthquake after defining the boundary between normal and anomalous values. According to the chart analysis, increased proton density occurred in 40 of the 50 cases observed, whereas increased proton velocity appeared in 28 of the 50 cases. Using hypergeometrical probability and an unbiased test with randomly generated parameters, the discovered correlation was statistically verified. A retrospective selection bias analysis is also provided in the research paper.

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Large-scale electron solar wind parameters of the inner heliosphere with Parker Solar Probe/FIELDS

10.5194/egusphere-egu2020-18573 ◽

2020 ◽

Author(s):

Karine Issautier ◽

Mingzhe Liu ◽

Michel Moncuquet ◽

Nicole Meyer-Vernet ◽

Milan Maksimovic ◽

...

Keyword(s):

Solar Wind ◽

Large Scale ◽

Statistical Study ◽

Solar Wind Speed ◽

The Sun ◽

Solar Wind Parameters ◽

Power Law Index ◽

Probe Mission ◽

Inner Heliosphere

We present in situ properties of electron density and temperature in the inner heliosphere obtained during the three first solar encounters at 35 solar radii of the Parker Solar Probe mission. These preliminary results, recently shown by Moncuquet et al., ApJS, 2020, are obtained from the analysis of the plasma quasi-thermal noise (QTN) spectrum measured by the radio RFS/FIELDS instrument along the trajectories extending between 0.5 and 0.17 UA from the Sun, revealing different states of the emerging solar wind, five months apart. The temperature of the weakly collisional core population varies radially with a power law index of about -0.8, much slower than adiabatic, whereas the temperature of the supra-thermal population exhibits a much flatter radial variation, as expected from its nearly collisionless state. These measured temperatures are close to extrapolations towards the Sun of Helios measurements.We also present a statistical study from these in situ electron solar wind parameters, deduced by QTN spectroscopy, and compare the data to other onboard measurements. In addition, we focus on the large-scale solar wind properties. In particular, from the invariance of the energy flux, a direct relation between the solar wind speed and its density can be deduced, as we have already obtained based on Wind continuous in situ measurements (Le Chat et al., Solar Phys., 2012). We study this anti-correlation during the three first solar encounters of PSP.

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Origin and Acceleration of Fast and Slow Solar Wind

Symposium - International Astronomical Union ◽

10.1017/s0074180900182609 ◽

2004 ◽

Vol 219 ◽

pp. 563-574

Author(s):

Giannina Poletto

Keyword(s):

Solar Wind ◽

Spectral Range ◽

High Speed ◽

Heliocentric Distance ◽

Coronal Plasma ◽

Slow Solar Wind ◽

Controversial Issues ◽

Heliospheric Observatory ◽

Slow Wind

Before the advent of the Solar and Heliospheric Observatory (SOHO, launched in 1995), we had little information on how coronal plasma gets accelerated to the high speed measured in situ. The Ultraviolet Coronagraph Spectrometer (UVCS) on SOHO, acquiring UV data over the first few solar radii, a region unexplored in this spectral range, allowed us to build a profile of the outflow plasma speed vs. heliocentric distance, based on empirical constraints. Still, much has to be learnt about the behavior of solar wind in the extended corona. In the following, after briefly reviewing the general properties of the solar wind, I'll focus on controversial issues — like the identification of the sources of fast and slow wind, and the acceleration of fast vs. slow wind streams — and I'll illustrate recent contributions to the solution of these problems.

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In-situ observations of the latitudinal gradients of the solar wind parameters during 1976 and 1977

Solar Physics ◽

10.1007/bf00159093 ◽

1986 ◽

Vol 104 (2) ◽

pp. 431-445 ◽

Cited By ~ 42

Author(s):

R. Bruno ◽

U. Villante ◽

B. Bavassano ◽

R. Schwenn ◽

F. Mariani

Keyword(s):

Solar Wind ◽

Latitudinal Gradients ◽

In Situ Observations ◽

Solar Wind Parameters

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Synoptic maps of solar wind parameters from in situ spacecraft observations

Journal of Geophysical Research Atmospheres ◽

10.1029/94ja02629 ◽

1995 ◽

Vol 100 (A3) ◽

pp. 3383-3393 ◽

Cited By ~ 4

Author(s):

P. R. Gazis

Keyword(s):

Solar Wind ◽

Solar Wind Parameters

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Solar-wind predictions for the Parker Solar Probe orbit

Astronomy and Astrophysics ◽

10.1051/0004-6361/201731831 ◽

2018 ◽

Vol 611 ◽

pp. A36 ◽

Cited By ~ 9

Author(s):

M. S. Venzmer ◽

V. Bothmer

Keyword(s):

Solar Wind ◽

Solar Activity ◽

Solar Corona ◽

Wind Model ◽

Wind Environment ◽

Frequency Distributions ◽

Solar Wind Model ◽

Solar Wind Parameters ◽

Inner Heliosphere

Context. The Parker Solar Probe (PSP; formerly Solar Probe Plus) mission will be humanitys first in situ exploration of the solar corona with closest perihelia at 9.86 solar radii (R⊙) distance to the Sun. It will help answer hitherto unresolved questions on the heating of the solar corona and the source and acceleration of the solar wind and solar energetic particles. The scope of this study is to model the solar-wind environment for PSPs unprecedented distances in its prime mission phase during the years 2018 to 2025. The study is performed within the Coronagraphic German And US SolarProbePlus Survey (CGAUSS) which is the German contribution to the PSP mission as part of the Wide-field Imager for Solar PRobe.Aim. We present an empirical solar-wind model for the inner heliosphere which is derived from OMNI and Helios data. The German-US space probes Helios 1 and Helios 2 flew in the 1970s and observed solar wind in the ecliptic within heliocentric distances of 0.29 au to 0.98 au. The OMNI database consists of multi-spacecraft intercalibrated in situ data obtained near 1 au over more than five solar cycles. The international sunspot number (SSN) and its predictions are used to derive dependencies of the major solar-wind parameters on solar activity and to forecast their properties for the PSP mission.Methods. The frequency distributions for the solar-wind key parameters, magnetic field strength, proton velocity, density, and temperature, are represented by lognormal functions. In addition, we consider the velocity distributions bi-componental shape, consisting of a slower and a faster part. Functional relations to solar activity are compiled with use of the OMNI data by correlating and fitting the frequency distributions with the SSN. Further, based on the combined data set from both Helios probes, the parameters frequency distributions are fitted with respect to solar distance to obtain power law dependencies. Thus an empirical solar-wind model for the inner heliosphere confined to the ecliptic region is derived, accounting for solar activity and for solar distance through adequate shifts of the lognormal distributions. Finally, the inclusion of SSN predictions and the extrapolation down to PSPs perihelion region enables us to estimate the solar-wind environment for PSPs planned trajectory during its mission duration.Results. The CGAUSS empirical solar-wind model for PSP yields dependencies on solar activity and solar distance for the solar-wind parameters’ frequency distributions. The estimated solar-wind median values for PSPs first perihelion in 2018 at a solar distance of 0.16 au are 87 nT, 340 km s−1, 214 cm−3, and 503 000 K. The estimates for PSPs first closest perihelion, occurring in 2024 at 0.046 au (9.86 R⊙), are 943 nT, 290 km s−1, 2951 cm−3, and 1 930 000 K. Since the modeled velocity and temperature values below approximately 20 R⊙appear overestimated in comparison with existing observations, this suggests that PSP will directly measure solar-wind acceleration and heating processes below 20 R⊙ as planned.

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SOHO – an Observatory to Study the Solar Interior and the Solar Atmosphere

International Astronomical Union Colloquium ◽

10.1017/s0252921100077125 ◽

1990 ◽

Vol 123 ◽

pp. 277-284

Author(s):

A.I. Poland ◽

V. Domingo

Keyword(s):

Solar Wind ◽

Solar Atmosphere ◽

Joint Venture ◽

Solar Interior ◽

Lagrangian Point ◽

Heliospheric Observatory ◽

Heating Mechanism ◽

The Earth ◽

Soho Spacecraft

AbstractThe Solar and Heliospheric Observatory, Soho, is a joint venture of ESA and NASA. The main objectives of Soho are: a) the study and understanding of solar coronal phenomena; and b) the study of the solar structure and interior dynamics from its core to the photosphere. The primary goals of the coronal and solar wind studies are to understand the coronal heating mechanism and its expansion into the solar wind.These goal will be achieved both by remote sensing of the solar atmosphere with high resolution spectrometers and telescopes and by “in situ” measurement of the composition and energy of the resulting solar wind and the energetic particles that propagate through it. The structure and interior dynamics will be studied by helio-seismological methods and the measurement of solar irradiance variations. The Soho spacecraft will be three-axis stabilized and located in a halo orbit around the L1 Lagrangian point (approximately 1% of the distance from the Earth to the Sun). It is currently scheduled for launch in July 1995.

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Relating CME density derived from remote sensing data to CME sheath solar wind plasma pile up as measured in-situ

10.5194/egusphere-egu2020-3341 ◽

2020 ◽

Author(s):

Manuela Temmer ◽

Lukas Holzknecht ◽

Mateja Dumbovic ◽

Bojan Vrsnak ◽

Nishtha Sachdeva ◽

...

Keyword(s):

Solar Wind ◽

Magnetic Structure ◽

Interplanetary Space ◽

Remote Sensing Data ◽

Solar Wind Plasma ◽

Proton Density ◽

Observational Assessment ◽

Sheath Region ◽

Pile Up

For better estimating the drag force acting on coronal mass ejections (CMEs) in interplanetary space and ram-pressure at planets, improved knowledge of the evolution of CME density/mass is highly valuable. We investigate a sample of 29 well observed CME-ICME events, for which we determine the de-projected 3D mass (STEREO-A and -B data), and the CME volume using GCS modeling (STEREO, SoHO). Expanding the volume to 1AU distance, we derive the density and compare the results to in-situ proton density measurements separately for the ICME sheath and magnetic structure. A fair agreement between calculated and measured density is derived for the magnetic structure as well for the sheath if taking into account mass pile up of solar wind plasma. We give evidence and observational assessment that during the interplanetary propagation of a CME 1) the magnetic structure has rather constant mass and 2) the sheath region at the front of the driver is formed from piled-up mass that is rather depending on the solar wind density ahead of the CME, than on the CME speed.&#160;

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A solar-wind-driven empirical model of Pc3 wave activity at a mid-latitude location

Annales Geophysicae ◽

10.5194/angeo-33-225-2015 ◽

2015 ◽

Vol 33 (2) ◽

pp. 225-234 ◽

Cited By ~ 2

Author(s):

S. Lotz ◽

B. Heilig ◽

P. Sutcliffe

Keyword(s):

Solar Wind ◽

Wind Speed ◽

Solar Wind Speed ◽

Cone Angle ◽

Wave Activity ◽

Proton Density ◽

Propagation Time ◽

Field Orientation ◽

Data Set ◽

Solar Wind Parameters

Abstract. In this paper we describe the development of two empirical models of Pc3 wave activity observed at a ground station. The models are tasked to predict pulsation intensity at Tihany, Hungary, from the OMNI solar wind data set at 5 min time resolution. One model is based on artificial neural networks and the other on multiple linear regression. Input parameters to the models are iteratively selected from a larger set of candidate inputs. The optimal set of inputs are solar wind speed, interplanetary magnetic field orientation (via cone angle), proton density and solar zenith angle (representing local time). Solar wind measurements are shifted in time with respect to Pc3 data to account for the propagation time of ULF perturbations from upstream of the bow shock. Both models achieve correlation of about 70% between measured and predicted Pc3 wave intensity. The timescales at which the most important solar wind parameters influence pulsation intensity are calculated for the first time. We show that solar wind speed influences pulsation intensity at much longer timescales (about 2 days) than cone angle (about 1 h).

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