Erratum to: “Influence of external conditions on physical processes and plasma parameters in a model of a high-frequency hybrid plasma system”

<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 Alfv&#233;n 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, Alfv&#233;nic 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>

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Modeling the Conditions for Microdroplets Formation and their Detachment from the Molten Metal on the Electrode

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.313.1 ◽

2021 ◽

Vol 313 ◽

pp. 1-7

Author(s):

V.D. Sarychev ◽

S.A. Solodsky ◽

Sergey A. Nevskii ◽

M.A. Kuznetsov ◽

D.P. Ilyaschenko ◽

...

Keyword(s):

Mathematical Model ◽

Molten Metal ◽

High Frequency ◽

Plasma Discharge ◽

Pulse Action ◽

Materials Processing ◽

Physical Processes ◽

Micro Scale ◽

Physical Mechanisms ◽

Frequency Pulse

Formation of nanostructure states on the surface of materials exposed to concentrated flows of energy is one of the relevant problems of modern materials processing. In the paper the authors describe the mechanism of the micro-scale droplets formation based on the study and modeling of the physical processes and technological aspects of the interaction between the heterogenic plasma flows and the molten substance at the electrode tip. The authors show new physical mechanisms and criteria for micro-and nanoparticles origination, develop a physical-mathematical model of the interaction between the molten metal and the plasma discharge with imposed high-frequency pulse action.

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Modelling the solar wind interaction with Mercury by a quasi-neutral hybrid model

Annales Geophysicae ◽

10.5194/angeo-21-2133-2003 ◽

2003 ◽

Vol 21 (11) ◽

pp. 2133-2145 ◽

Cited By ~ 74

Author(s):

E. Kallio ◽

P. Janhunen

Keyword(s):

Solar Wind ◽

Plasma Physics ◽

Hybrid Model ◽

Space Plasma ◽

Physical Processes ◽

Space Plasma Physics ◽

Solar Wind Interaction ◽

Plasma Parameters ◽

Advantages And Disadvantages ◽

Self Consistent

Abstract. Quasi-neutral hybrid model is a self-consistent modelling approach that includes positively charged particles and an electron fluid. The approach has received an increasing interest in space plasma physics research because it makes it possible to study several plasma physical processes that are difficult or impossible to model by self-consistent fluid models, such as the effects associated with the ions’ finite gyroradius, the velocity difference between different ion species, or the non-Maxwellian velocity distribution function. By now quasi-neutral hybrid models have been used to study the solar wind interaction with the non-magnetised Solar System bodies of Mars, Venus, Titan and comets. Localized, two-dimensional hybrid model runs have also been made to study terrestrial dayside magnetosheath. However, the Hermean plasma environment has not yet been analysed by a global quasi-neutral hybrid model. In this paper we present a new quasi-neutral hybrid model developed to study various processes associated with the Mercury-solar wind interaction. Emphasis is placed on addressing advantages and disadvantages of the approach to study different plasma physical processes near the planet. The basic assumptions of the approach and the algorithms used in the new model are thoroughly presented. Finally, some of the first three-dimensional hybrid model runs made for Mercury are presented. The resulting macroscopic plasma parameters and the morphology of the magnetic field demonstrate the applicability of the new approach to study the Mercury-solar wind interaction globally. In addition, the real advantage of the kinetic hybrid model approach is to study the property of individual ions, and the study clearly demonstrates the large potential of the approach to address these more detailed issues by a quasi-neutral hybrid model in the future.Key words. Magnetospheric physics (planetary magnetospheres; solar wind-magnetosphere interactions) – Space plasma physics (numerical simulation studies)

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Interaction between High Frequency Oscillations and Low Frequency Oscillations in Beam-Plasma System

Journal of the Physical Society of Japan ◽

10.1143/jpsj.23.1430 ◽

1967 ◽

Vol 23 (6) ◽

pp. 1430-1431 ◽

Cited By ~ 7

Author(s):

Takaya Kawabe ◽

Yoshinobu Kawai ◽

Kazuo Takayama ◽

Shoji Kojima

Keyword(s):

High Frequency ◽

Low Frequency ◽

Plasma System ◽

High Frequency Oscillations ◽

Low Frequency Oscillations ◽

Beam Plasma

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Efficient and reliable surge prevention algorithm for centrifugal compressor

Aircraft Engineering and Aerospace Technology ◽

10.1108/aeat-11-2018-0284 ◽

2020 ◽

Vol 92 (1) ◽

pp. 47-59

Author(s):

Grzegorz Liśkiewicz

Keyword(s):

Working Conditions ◽

High Frequency ◽

Experimental Studies ◽

Phase Portraits ◽

Centrifugal Blower ◽

Local Flow ◽

Content Type ◽

Operating Range ◽

Surge Margin ◽

External Conditions

Purpose The paper aims to present an outline of the technology of the active anti-surge algorithm based on high-frequency pressure measurement. The presented system is fast, inexpensive and reliable and does not limit the machine-operating range. Many contemporary anti-surge systems are based on theoretical surge margin. This solution limits machine operating range by about 10-15 per cent in the region of the highest pressure ratios. It is also often sensitive to change in external conditions such as temperature or density, as the system reacts to limits calculated theoretically. Design/methodology/approach This paper presents results of pressure measurements obtained on the low-speed centrifugal blower DP1.12. The pressure signals were presented in the form of phase diagrams, and conclusions were drawn from their phase portraits to develop the surge indication parameter. Findings The presented safety system uses the signal to develop the so-called (rate of derivative fluctuation) RDF parameter. In nominal working conditions, this parameter keeps the value close to 1. When RDF reaches values over 3, the anti-surge procedure should be implemented. Experimental studies have shown that this algorithm assures enough time to incur actions suppressing unstable phenomena. Originality/value The system reacts to real machine working conditions and is hence reliable. The RDF algorithm could also be used to identify local flow instabilities, as well as off-design operation.

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On High Frequency Polar Motion and Length of Day Variations

International Astronomical Union Colloquium ◽

10.1017/s0252921100061716 ◽

2000 ◽

Vol 178 ◽

pp. 545-554

Author(s):

K. Arfa-Kaboodvand ◽

E. Groten

Keyword(s):

Frequency Spectrum ◽

Earth Rotation ◽

High Frequency ◽

Polar Motion ◽

Length Of Day ◽

Physical Processes ◽

Earth Orientation ◽

Tidal Forces ◽

Diurnal Range ◽

Insight Into

AbstractThe 0.042-day Earth rotation data (diurnal and semidiurnal) computed by the International GPS Service were used to analyze the daily/sub-daily variations of polar motion (PM) and length of day (LOD). Systematic and advanced spectral analytical investigations of the degree of periodic variability have been carried out. They show that the prominent periodical components can be found at the tidal frequencies of zonal, tesseral and sectorial waves. These investigations should give better insight into the physical processes, which influence Earth orientation (i.e. due to the atmospheric and oceanic motions, tidal forces etc.). It should be the basis for the detailed modeling of excitation functions in the sub-diurnal range of the high-frequency spectrum.

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In situ measurements of sub-meter plasma waves over low-latitude ionosphere during Leonid-99 meteor storm

Annales Geophysicae ◽

10.5194/angeo-22-2033-2004 ◽

2004 ◽

Vol 22 (6) ◽

pp. 2033-2036

Author(s):

S. P. Gupta ◽

R. Sekar ◽

Y. B. Acharya

Keyword(s):

High Frequency ◽

Plasma Waves ◽

Plasma Parameters ◽

Low Latitude ◽

Scale Size ◽

Meteor Storm ◽

Low Latitude Ionosphere ◽

First Time ◽

Probe Measurements

Abstract. In situ probe measurements of plasma parameters were carried out on 18 and 20 November 1999 from Sriharikota, India, a low-latitude rocket launching station to investigate the effect of a Leonid meteor storm. Results obtained on plasma waves using a high frequency Langmuir probe are discussed. The characteristics of the sub-meter scale size plasma waves observed for the first time during Leonid meteor storm are presented. Based on the results obtained from both the rocket flights and comparison with the results obtained from previous rocket flights from the same location, it appears these sub-meter waves are associated with intense meteoric activity. A possible mechanism based on the dependence of the meteoric activity and its limitations are discussed.

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