What can Observations of Comets Tell Us about the Solar Wind at the Maunder Minimum?

AbstractThis paper discussed whether 17th Century observers left historical records of the plasma tails of comets that would be adequate to enable us to extract the physical parameters of the solar wind. The size of the aberration angle between a comet’s tail and its radius-vector defines the type of the tail: plasma or dust. We considered Bredikhin’s calculations of the parameters for 10 comet tails observed during the Maunder minimum (1645 – 1715). For those comets the angle between the tail’s axis and the radius-vector on average exceeded the value of 10° that is typical for dust tails. It was noted that visual observations of the ion tails of comets are very difficult to make owing to the spectral composition of their radiation, confirming the conclusion that observations of comet tails made in the 17th Century are not suitable for deriving past values of the physical parameters of the solar wind.

Download Full-text

Empirical inner boundary conditions and rotation rates for solar wind models

10.5194/egusphere-egu21-782 ◽

2021 ◽

Author(s):

Huw Morgan

Keyword(s):

Magnetic Field ◽

Solar Wind ◽

Boundary Conditions ◽

Coronal Magnetic Field ◽

Height Range ◽

Rotation Rates ◽

Wind Structure ◽

Solar Wind Structure ◽

Coronal Electron ◽

Made In

To date, the inner boundary conditions for solar wind models are either directly or indirectly based on magnetic field extrapolation models of the photosphere. Furthermore, between the photosphere and Earth, there are no other direct empirical constraints on models. New breakthroughs in coronal rotation tomography, applied to coronagraph observations, allow maps of the coronal electron density to be made in the heliocentric height range 4-12 solar radii (Rs). We show that these maps (i) give a new empirical boundary condition for solar wind structure at a height where the coronal magnetic field has become radial, thus avoiding the need to model the complex inner coronal magnetic field, and (ii) give accurate rotation rates for the corona, of crucial importance to the accuracy of solar wind models and forecasts.

Download Full-text

Progress on Coronal, Interplanetary, Foreshock, and Outer Heliospheric Radio Emissions

Publications of the Astronomical Society of Australia ◽

10.1071/as00022 ◽

2000 ◽

Vol 17 (1) ◽

pp. 22-34 ◽

Cited By ~ 16

Author(s):

Iver H. Cairns ◽

P. A. Robinson ◽

G. P. Zank

Keyword(s):

Solar Wind ◽

Plasma Waves ◽

Recent Theory ◽

Type Ii ◽

Solar Radio Bursts ◽

Radio Emissions ◽

Source Regions ◽

Earth’S Bow Shock ◽

Made In

AbstractType II and III solar radio bursts are associated with shock waves and streams of energetic electrons, respectively, which drive plasma waves and radio emission at multiples of the electron plasma frequency as they move out from the corona into the interplanetary medium. Analogous plasma waves and radiation are observed from the foreshock region upstream of Earth's bow shock. In situ spacecraft observations in the solar wind have enabled major progress to be made in developing quantitative theories for these phenomena that are consistent with available data. Similar processes are believed responsible for radio emissions at 2–3 kHz that originate in the distant heliosphere, from where the solar wind interacts with the local interstellar medium. The primary goal of this paper is to review the observations and theories for these four classes of emissions, focusing on recent progress in developing detailed theories for the plasma waves and radiation in the source regions. The secondary goal is to introduce and review stochastic growth theory, a recent theory which appears quantitatively able to explain the wave observations in type III bursts and Earth's foreshock and is a natural theory to apply to type II bursts, the outer heliospheric emissions, and perhaps astrophysicalemissions.

Download Full-text

Power spectral density of magnetic field and ion velocity fluctuations from inertial to kinetic ranges

10.5194/egusphere-egu21-2837 ◽

2021 ◽

Author(s):

Jana Šafránková ◽

Zdeněk Němeček ◽

František Němec ◽

Luca Franci ◽

Alexander Pitňa

Keyword(s):

Magnetic Field ◽

Solar Wind ◽

Large Scale ◽

Collisionless Plasma ◽

Power Spectra ◽

Physical Parameters ◽

Particle In Cell ◽

High Reynolds ◽

Experimental Findings ◽

Turbulent Cascade

The solar wind is a unique laboratory to study the turbulent processes occurring in a collisionless plasma with high Reynolds numbers. A turbulent cascade&#8212;the process that transfers the free energy contained within the large scale fluctuations into the smaller ones&#8212;is believed to be one of the most important mechanisms responsible for heating of the solar corona and solar wind. The paper analyzes power spectra of solar wind velocity, density and magnetic field fluctuations that are computed in the frequency range around the break between inertial and kinetic scales. The study uses measurements of the Bright Monitor of the Solar Wind (BMSW) on board the Spektr-R spacecraft with a time resolution of 32 ms complemented with 10 Hz magnetic field observations from the Wind spacecraft propagated to the Spektr-R location. The statistics based on more than 42,000 individual spectra show that: (1) the spectra of both quantities can be fitted by two (three in the case of the density) power-law segments; (2) the median slopes of parallel and perpendicular fluctuation velocity and magnetic field components are different; (3) the break between MHD and kinetic scales as well as the slopes are mainly controlled by the ion beta parameter. These experimental results are compared with high-resolution 2D hybrid particle-in-cell simulations, where the electrons are considered to be a massless, charge-neutralizing fluid with a constant temperature, whereas the ions are described as macroparticles representing portions of their distribution function. In spite of several limitations (lack of the electron kinetics, lower dimensionality), the model results agree well with the experimental findings. Finally, we discuss differences between observations and simulations in relation to the role of important physical parameters in determining the properties of the turbulent cascade.

Download Full-text

The response of geomagnetic spectral composition to solar wind during storm time

Journal of Atmospheric and Terrestrial Physics ◽

10.1016/0021-9169(85)90081-9 ◽

1985 ◽

Vol 47 (8-10) ◽

pp. 1017-1022 ◽

Cited By ~ 2

Author(s):

Xiaoping Zeng ◽

Yunfang Lin ◽

Donqi Yao ◽

Qihua Guo

Keyword(s):

Solar Wind ◽

Spectral Composition

Download Full-text

One-dimensional dislocations. I. Static theory

Proceedings of the Royal Society of London Series A - Mathematical and Physical Sciences ◽

10.1098/rspa.1949.0095 ◽

1949 ◽

Vol 198 (1053) ◽

pp. 205-216 ◽

Cited By ~ 1182

Keyword(s):

Critical Conditions ◽

Dislocation Model ◽

Physical Parameters ◽

Spontaneous Generation ◽

Static Theory ◽

One Dimensional ◽

Lennard Jones ◽

Regular Sequences ◽

Crystalline Substrate ◽

Made In

The theory of a one-dimensional dislocation model is developed. Besides acting as a pointer to developments of general dislocation theory, it has a variety of direct physical applications, particularly to monolayers on a crystalline substrate and to conditions in the edge row of a terrace of molecules in a growing crystal. Allowance is made in the theory for a difference in natural lattice-spacing between the surface layer or row and the substrate. The form and energy of single dislocations and of regular sequences of dislocations are calculated. Critical conditions for spontaneous generation (or escape) of dislocations are determined, and likewise the activation energies for such processes below the critical limits. Various physical applications of the model are discussed, and the physical parameters are evaluated with the aid of the Lennard-Jones force law for the above-mentioned principal applications.

Download Full-text

Reinforcement of Prefabricate Concrete Beams with Basalt-Epoxy Bars

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1020.275 ◽

2014 ◽

Vol 1020 ◽

pp. 275-279

Author(s):

Marlena Rajczyk ◽

Bartłomiej Stachecki

Keyword(s):

Numerical Modeling ◽

Concrete Beam ◽

Concrete Beams ◽

Physical Parameters ◽

Modern Engineering ◽

New Construction ◽

Prefabricated Structure ◽

Reinforcement Conditioning ◽

Made In ◽

Composite Reinforcement

The article presents a way of reinforcing concrete beams with innovative composite materials in the form of basaltic-epoxy bars. Considering the carrying the element out in the technology of the prefabrication, the main assumptions and aims of the method and economic conditioning were described. Examples of domestic, modern engineering objects made in the prefabricated structure were expressed. The particular attention was devoted to the issue of the cover of the composite reinforcement conditioning the permanence of the ready element. In the part of the article devoted to the numerical analysis of the new construction, is characterized the most important mechanical and physical parameters of used composite bars and presented the assumptions of the method of the numerical modeling of beams subjected to clean bending. For the optimum evaluation of the element a research set was prepared in the form of the reinforced beam by composite bars, and another one by steel rods and concrete beam without the reinforcement - enabling evaluation of the correctness of the method. The analysis is opening the doors for the more accurately research on the usefulness of the composite reinforcement of the concrete prefabrication to the modern construction.

Download Full-text

Evaluation of Physical Parameters of a Clay with the Incorporation of Industrial Ash Waste by Means of Variance Analysis

Materials Science Forum ◽

10.4028/www.scientific.net/msf.881.379 ◽

2016 ◽

Vol 881 ◽

pp. 379-382

Author(s):

Francine Machado Nunes ◽

C.C. Ferreira ◽

Flávio André Pavan ◽

M.X. Guterres ◽

L.M.H. Quintana

Keyword(s):

Waste Disposal ◽

Industrial Waste ◽

Rice Husk Ash ◽

Raw Materials ◽

Bottom Ash ◽

Physical Parameters ◽

Physical Tests ◽

Normative Standard ◽

Made In ◽

Sheep Wool

This work evaluates the incorporation of solid industrial waste such as rice husk ash, bottom ash from mineral coal and ash coming from the washing of sheep wool in Red Ceramic Mass (MRC) composed of clay. These raw materials were collected from industries in the municipality of Bagé-RS, Brazil. Percentages of 0, 5, 10, 20 and 30% of these wastes were added to (MRC) in order to reduce the environmental impacts, both by the clay extraction as well as for waste disposal. The physical tests (Atterberg limits) made with the clay, follow a normative standard. However, the tests made in the formulations served to compare the formulations’ behavior in relation to the clay. In order to verify if the tests proposed in (MRC) and if the formulations have changed significantly the investigated indexes, an Analysis of Variance (ANOVA) was performed. The results generally indicate that there are statistically significant differences, mainly regarding the Plasticity Index (PI) and the Liquidity Limit (LL), as ash was added in the formulations.

Download Full-text

Radon over Kimberlite Pipes: Surface Field Experiments and Calculations of Vertical Diffusion (Arkhangelsk Diamondiferous Province, NW Russia)

Applied Sciences ◽

10.3390/app112411765 ◽

2021 ◽

Vol 11 (24) ◽

pp. 11765

Author(s):

Evgeny Yakovlev ◽

Andrey Puchkov

Keyword(s):

Field Experiments ◽

Gas Permeability ◽

Sedimentary Rocks ◽

Experimental Studies ◽

Physical Parameters ◽

Vertical Diffusion ◽

Diffusion Transfer ◽

Emanation Method ◽

Kimberlite Field ◽

Made In

We present the results of field and experimental studies to assess the influence on the formation of the radon field over the kimberlite pipes of the Arkhangelsk diamondiferous province. Measurements were made in the field to establish the radon radiation in the soil air and the gas permeability of soils in the area of the Chidvinskaya pipe. Experimental work was aimed at determining the radiation and physical parameters of the rocks occurring within the kimberlite field. Based on a set of field and experimental data, a model of the diffusion transfer of radon in the area of the Chidvinskaya pipe was calculated for three profiles, represented by the rocks of the pipe, sedimentary rocks of the exocontacts of the pipe, and host sandy and clay sedimentary rocks. The results of the calculations show that the rocks of the exocontacts of the pipe have the greatest potential for increased radon radiation. The calculated values of the radon radiation produced by these rocks exceeded 9000 Bq·m−3. The diatreme kimberlites produced the lowest radon radiation. We showed that the source of the increased values of radon radiation is the rocks of the pipe’s exocontacts. This fact will make it possible to use the emanation method as an additional one for the search for kimberlite pipes.

Download Full-text

Mitigasi Spritual dalam Naskah Lontar Roga Sanghara Bhumi

Sanjiwani: Jurnal Filsafat ◽

10.25078/sjf.v10i1.1629 ◽

2020 ◽

Vol 10 (1) ◽

pp. 27

Author(s):

I Nyoman Suka Ardiyasa

Keyword(s):

Historical Records ◽

The Public ◽

Major Earthquake ◽

The Past ◽

The World ◽

Community People ◽

Made In

The island of Bali is an island very vulnerable to disaster, it is proven with historical records that Bali has experienced a major earthquake better known as Gejer Bali. Various efforts have been made by the community from the past until now in the effort of mitigation done in sekala and niskala. In the community, people believe that if they want to avoid the disaster then the community must implement the tri hita karana, while niskala (theologically) done with various upakara. Upakara sources and the types of disasters that occur in this world are believed to be contained in the Lontar Roga Sanghara Bhumi manuscript. But the existence of the manuscript is not much to know so it is necessary to conduct a more in-depth review so that it can be disseminated to the public. To focus on these reviews, we focused on three problem formulas: analyzing the summary of the Roga Sanghara Bhumi lontar manuscripts, the types of disasters mentioned in the Roga Sanghara Bhumi lontar, and the theological attempts made in dealing with the disasters mentioned in lontar Roga Sanghara Bhumi.From the results of the study conducted it is briefly known that the lontar Roga Sanghara Bhumi contains about the causes of catastrophe or disaster occurred in the world, the types of catastrophes or disasters that can occur in the world and some characteristics of the coming disaster or disaster, while the types The disaster mentioned in the lontar of Roga Sanghara Bhumi is a type of disaster that repeats every sasih it and the kind of disaster that occurs which is seen from the bad gesture, in the concept of Lontar Roga Sanghara Bhumi called Durmanggala. The theological efforts undertaken in tackling the disasters mentioned in the lontar of Roga Sanghara Bhumi are performing ceremonies that are shown to Ida Sang Hyang Widhi Wasa with the aim of pleading for salvation such as Prayascita Ceremony, Master Piduka, Labuh Gentuh, Jagat, Pamahayu Bumi and Nangluk Mrana. All these ceremonies are theological (mitigation) efforts in reducing disaster risks that occur on earth.

Download Full-text

Spectroscopy of a Solar Prominence with the Narrow-Bandpass Filter

International Astronomical Union Colloquium ◽

10.1017/s0252921100025562 ◽

1994 ◽

Vol 144 ◽

pp. 343-344

Author(s):

P. Rudawy

Keyword(s):

Optical Thickness ◽

Large Scale ◽

Bandpass Filter ◽

Solar Limb ◽

Physical Parameters ◽

Two Dimensional ◽

Line Profiles ◽

Solar Prominence ◽

Quiescent Prominence ◽

Made In

AbstractObservations and analysis of a quiescent prominence above the solar limb are presented. The set of quasi-monochromatic images of the prominence made in a few wavelengths of Hα, Hβand D3lines have been used for reconstruction of the coarse line profiles. Two-dimensional maps of the main physical parameters of the prominence matter-macroscopic and turbulent velocities, electron temperature, density and optical thickness have been constructed. Presented method of low-resolution spectroscopy is useful for investigations of the variety of large-scale solar phenomena.

Download Full-text