scholarly journals Whistler critical Mach number and electron acceleration at the bow shock: Geotail observation

2006 ◽  
Vol 33 (24) ◽  
Author(s):  
M. Oka ◽  
T. Terasawa ◽  
Y. Seki ◽  
M. Fujimoto ◽  
Y. Kasaba ◽  
...  
Keyword(s):  
Mach Number ◽  
Electron Acceleration ◽  
Bow Shock ◽  
Critical Mach Number

ABOUT CONSTRUCTION OF FLAT BODIES WITH INCREASED CRITICAL MACH NUMBER

2016 ◽  
Vol 47 (6) ◽  
pp. 563-579
Author(s):  
Sergey Alexandrovich Takovitskii
Keyword(s):  
Mach Number ◽  
Critical Mach Number

Microinstabilities associated with a high Mach number, perpendicular bow shock

1984 ◽  
Vol 37 (1-2) ◽  
Author(s):  
C.S. Wu ◽  
D. Winske ◽  
Y.M. Zhou ◽  
S.T. Tsai ◽  
P. Rodriguez ◽  
...  
Keyword(s):  
Mach Number ◽  
Bow Shock ◽  
High Mach Number ◽  
High Mach

scholarly journals Critical Mach Numbers of Flow around Two-Dimensional and Axisymmetric Bodies

Aerodynamics ◽  
2021 ◽  
Author(s):  
Vladimir Frolov
Keyword(s):  
Mach Number ◽  
Cross Section ◽  
Flow Simulation ◽  
The Body ◽  
Two Dimensional ◽  
Critical Mach Number ◽  
Method Of Integral Relations ◽  
Viscosity Factor ◽  
Mach Numbers ◽  
Axisymmetric Bodies

The paper presents the calculated results obtained by the author for critical Mach numbers of the flow around two-dimensional and axisymmetric bodies. Although the previously proposed method was applied by the author for two media, air and water, this chapter is devoted only to air. The main goal of the work is to show the high accuracy of the method. For this purpose, the work presents numerous comparisons with the data of other authors. This method showed acceptable accuracy in comparison with the Dorodnitsyn method of integral relations and other methods. In the method under consideration, the parameters of the compressible flow are calculated from the parameters of the flow of an incompressible fluid up to the Mach number of the incoming flow equal to the critical Mach number. This method does not depend on the means determination parameters of the incompressible flow. The calculation in software Flow Simulation was shown that the viscosity factor does not affect the value critical Mach number. It was found that with an increase in the relative thickness of the body, the value of the critical Mach number decreases. It was also found that the value of the critical Mach number for the two-dimensional case is always less than for the axisymmetric case for bodies with the same cross-section.

Kinetic simulations of high Mach shocks: PIC simulations vs in-situ measurements

2021 ◽  
Author(s):  
Artem Bohdan ◽  
Martin Pohl ◽  
Jacek Niemiec ◽  
Paul J. Morris ◽  
Yosuke Matsumoto ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Mach Number ◽  
Supernova Remnants ◽  
Large Scale ◽  
Bow Shock ◽  
Electron Heating ◽  
Weibel Instability ◽  
High Mach Number ◽  
High Mach

<p>High-Mach-number collisionless shocks are found in planetary systems and supernova remnants (SNRs). Electrons are heated at these shocks to temperatures well above the Rankine–Hugoniot prediction. However, the processes responsible for causing the electron heating are still not well understood. We use a set of large-scale particle-in-cell simulations of nonrelativistic shocks in the high-Mach-number regime to clarify the electron heating processes. The physical behavior of these shocks is defined by ion reflection at the shock ramp. Further interactions between the reflected ions and the upstream plasma excites electrostatic Buneman and two-stream ion–ion Weibel instabilities. Electrons are heated via shock surfing acceleration, the shock potential, magnetic reconnection, stochastic Fermi scattering, and shock compression. The main contributor is the shock potential. The magnetic field lines become tangled due to the Weibel instability, which allows for parallel electron heating by the shock potential. The constrained model of electron heating predicts an ion-to-electron temperature ratio within observed values at SNR shocks and in Saturn’s bow shock. We also present evidence for field amplification by the Weibel instability. The normalized magnetic field strength strongly correlates with the Alfvenic Mach number, as is in-situ observed at Saturn's bow shock.</p>

Shock Drift Electron Acceleration and Pitch Angle Scattering

2001 ◽  
Vol 203 ◽  
pp. 577-579
Author(s):  
M. Vandas
Keyword(s):  
Pitch Angle ◽  
Theoretical Calculations ◽  
Electron Acceleration ◽  
Bow Shock ◽  
Interplanetary Shocks ◽  
Energetic Electrons ◽  
Angle Scattering ◽  
Earth’S Bow Shock ◽  
Additional Process

Spacecraft measurements of energetic electrons in the vicinity of the Earth's bow shock and interplanetary shocks are analyzed and compared with theoretical calculations. It is concluded that shock drift acceleration of electrons is very modified by an additional process, probably by strong pitch angle scattering. Calculations including this effect are presented.

Estimates for critical Mach number under isoperimetric constraints

1995 ◽  
Vol 6 (5) ◽  
pp. 385-398 ◽  
Author(s):  
F. G. Avkhadiev ◽  
A. M. Elizarov ◽  
D. A. Fokin
Keyword(s):  
Mach Number ◽  
Subsonic Flow ◽  
Chaplygin Gas ◽  
Ideal Gas ◽  
Open Problems ◽  
Inverse Boundary ◽  
Critical Mach Number ◽  
Lindelöf Principle ◽  
Isoperimetric Constraints ◽  
Upper Estimate

The problem of maximization of the critical Mach number in a subsonic flow of an ideal gas is considered. The Chaplygin gas approximation and the integral representation of the solution of the inverse boundary-value problem of aerohydrodynamics are used to reduce the problem to a special minimax one. The exact solution of the latter is obtained on the basis of the Lindelöf principle. An upper estimate for the critical Mach number is obtained. The results are generalized for the case of airfoil cascades. Some open problems are described.

Low Drag Aerofoils

1947 ◽  
Vol 51 (433) ◽  
pp. 54-64
Author(s):  
L. G. Whitehead
Keyword(s):  
Mach Number ◽  
Surface Finish ◽  
Experimental Work ◽  
Theoretical Basis ◽  
High Standard ◽  
Critical Value ◽  
Aircraft Wing ◽  
Critical Mach Number ◽  
The Past ◽  
Design And Manufacture

During the past few years a new series of low drag aerofoils has been developed which represents a radical departure from earlier practice. The changes envisaged are much greater than those which accompanied the general change-over from the biplane to the monoplane, and give rise to many problems whose solution requires considerable theoretical and experimental work. An important feature of the new sections is the precision in design and manufacture which is essential for their success. This has given renewed interest to the investigation of many of the detailed problems of air flow and calls for parallel improvements in manufacturing technique so as to achieve the high standard of surface finish required.The purpose of this paper is to give a brief account of the theoretical basis of the design and application of the modified profiles as aircraft wing sections. It deals with the design of aerofoils for the subsonic range only, or, to be more precise, for flight at speeds below the critical Mach Number at which shock waves are first formed. The critical value usually lies in the range 0.6 to 0.8, depending on the wing shape and incidence, as will be described in more detail later.

Anomalous Flow Deflection at Earth’s Low-Alfvén-Mach-Number Bow Shock

2008 ◽  
Vol 101 (6) ◽  
Author(s):  
Masaki N. Nishino ◽  
Masaki Fujimoto ◽  
Tai-Duc Phan ◽  
Toshifumi Mukai ◽  
Yoshifumi Saito ◽  
...  
Keyword(s):  
Mach Number ◽  
Bow Shock ◽  
Flow Deflection
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