Finite Amplitude Compression Waves in a Collision-Free Plasma

1964 ◽  
Vol 7 (11) ◽  
pp. 1800 ◽  
Author(s):  
K. W. Morton
Keyword(s):  
Finite Amplitude ◽  
Compression Waves ◽  
Amplitude Compression ◽  
Free Plasma

Large-amplitude compression waves in an adiabatic two-fluid model of a collision-free plasma

1962 ◽  
Vol 14 (3) ◽  
pp. 369-384 ◽  
Author(s):  
K. W. Morton
Keyword(s):  
Steady State ◽  
Large Amplitude ◽  
Numerical Solutions ◽  
Discontinuous Solution ◽  
Compression Waves ◽  
Amplitude Compression ◽  
Mach Numbers ◽  
Steady State Solutions ◽  
Free Plasma ◽  
Two Fluid

The development of large amplitude compression waves in a collision-free plasma is studied by considering the motion of a plane piston into a uniform stationary plasma containing a magnetic field parallel to the plane of the piston. The adiabatic two-fluid equations are solved by finite-difference methods and the form of the waves after a long time is compared with the possible steady-state solutions.A generalized discontinuous solution of the steady-state equations is found for sufficiently high Mach numbers. At the highest Mach numbers this leads to a constant state at the piston; while at lower speeds a wave train results whose amplitude increases as the speed decreases. In each of these cases the numerical solutions of the time-dependent equations converge rapidly to the steady-state solutions. At still lower speeds, where the solitary-wave solution exists, the situation is less clear.

Low Mach Number Magnetic Compression Waves in a Collision-Free Plasma

1961 ◽  
Vol 4 (9) ◽  
pp. 1105 ◽  
Author(s):  
P. L. Auer ◽  
H. Hurwitz ◽  
R. W. Kilb
Keyword(s):  
Mach Number ◽  
Low Mach Number ◽  
Compression Waves ◽  
Magnetic Compression ◽  
Free Plasma

scholarly journals Finite Amplitude Effects of Torsional Alfvén Waves in a Flux Tube

1983 ◽  
Vol 102 ◽  
pp. 401-406
Author(s):  
⊘. Andreassen ◽  
P. Maltby
Keyword(s):  
Magnetic Flux ◽  
Flux Tube ◽  
Finite Amplitude ◽  
Successive Approximations ◽  
Wave Radiation ◽  
Magnetic Flux Tube ◽  
Method Of Successive Approximations ◽  
Magnetohydrodynamic Equations ◽  
Progressive Waves ◽  
Free Plasma

Consider a cylindrical, homogeneous magnetic flux tube embedded in a field-free compressible plasma. We employ the method of successive approximations to solve the magnetohydrodynamic equations analytically for an axisymmetrical (m=0) torsional Alfvén mode. The m=0 mode inside the tube may excite surface-, stationary- or progressive waves in the field-free plasma. We conclude that, in contrast to the linear theory, the flux tube may lose energy by wave radiation to the surroundings.

The structure of quasi-shocks in a collision-free plasma in a magnetic field

1967 ◽  
Vol 1 (1) ◽  
pp. 129-144 ◽  
Author(s):  
J. G. Cordey ◽  
P. G. Saffman
Keyword(s):  
Magnetic Field ◽  
Finite Amplitude ◽  
Mean Values ◽  
Turbulent Transition ◽  
Random Manner ◽  
Flow Through ◽  
Steady Solutions ◽  
Flow Variables ◽  
Hydromagnetic Waves ◽  
Free Plasma

A study is made of finite amplitude, oblique, hydromagnetic waves in a cold collision-free plasma. It is shown that the equations admit steady solutions which describe flow through a front. Ahead of the front, the flow is uniform, but behind the front the magnetic field and flow variables oscillate irregularly in a random manner. The fronts are called ‘quasi-shocks’, although they have more in common with the laminar-turbulent transition of fluid mechanics than with the classical shock wave. The structure of the quasi-shocks is examined, and estimates are made for the mean values behind the front. The relevance of the quasishocks to the so-called ‘collision-free shock’ is considered, and comparison is made with the ‘bow shock’ on the solar wind near the earth. It is shown that the quasi-shock is consistent with some of the observed data.

Studies on the Thromboplastic Effect of Human Plasma Lipoproteins

1976 ◽  
Vol 35 (01) ◽  
pp. 178-185 ◽  
Author(s):  
Helena Sandberg ◽  
Lars-Olov Andersson
Keyword(s):  
High Density Lipoprotein ◽  
Human Plasma ◽  
Platelet Rich Plasma ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Plasma Lipoproteins ◽  
Very Low Density Lipoprotein ◽  
Low Density ◽  
Free Plasma ◽  
Good Agreement

SummaryHuman plasma lipoprotein fractions were prepared by flotation in the ultracentrifuge. Addition of these fractions to platelet-rich, platelet-poor and platelet-free plasma affected the partial thromboplastin and Stypven clotting times to various degrees. Addition of high density lipoprotein (HDL) to platelet-poor and platelet-free plasma shortened both the partial thromboplastin and the Stypven time, whereas addition of low density lipoprotein and very low density lipoprotein (LDL + VLDL) fractions only shortened the Stypven time. The additions had little or no effect in platelet-rich plasma.Experiments involving the addition of anti-HDL antibodies to plasmas with different platelet contents and measuring of clotting times produced results that were in good agreement with those noted when lipoprotein was added. The relation between structure and the clot-promoting activity of various phospholipid components is discussed.

Stability of Prostacyclin in Human Plasma and Whole Blood: Studies on the Protective Effect of Albumin

1981 ◽  
Vol 46 (03) ◽  
pp. 645-647 ◽  
Author(s):  
M A Orchard ◽  
C Robinson
Keyword(s):  
Platelet Aggregation ◽  
Bovine Serum Albumin ◽  
Serum Albumin ◽  
Protective Effect ◽  
Whole Blood ◽  
Bovine Serum ◽  
Fatty Acid Content ◽  
Krebs Solution ◽  
Antiaggregatory Activity ◽  
Free Plasma

SummaryThe biological half-life of prostacyclin in Krebs solution, human cell-free plasma or whole blood was measured by bracket assay on ADP-induced platelet aggregation. At 37°C, pH 7.4, plasma and blood reduced the rate of loss of antiaggregatory activity compared with Krebs solution. The protective effect of plasma was greater than that of whole blood. This effect could be partially mimicked by the addition of human or bovine serum albumin to the Krebs solution. The stabilisation afforded by human serum albumin was dependent on the fatty acid content of the albumin, although this was less important for bovine serum albumin.

The Influence of Serotonin on Clot Retraction and the Thrombelastogram

1958 ◽  
Vol 02 (01/02) ◽  
pp. 111-124 ◽  
Author(s):  
E Deutsch ◽  
K Martiny
Keyword(s):  
Human Plasma ◽  
Human Platelet ◽  
Platelet Rich Plasma ◽  
Specific Effect ◽  
High Dose ◽  
Clot Retraction ◽  
Platelet Counts ◽  
Essential Value ◽  
High Doses ◽  
Free Plasma

Summary1. Normal platelets are necessary for induction of normal clot retraction.2. Serotonin does not induce retraction in human platelet-free plasma-clots or enhance clot firmness as measured in the coagulogram.3. Serotonin does not improve clot retraction or firmness in plasma clots with sub-optimal platelet counts.4. Methylserotonin inhibits clot retraction of platelet-rich plasma to a certain extent in moderate doses, whereas, high doses are ineffective. BOL 148 has a similar, but less significant action. There is a possibility that these effects are specific antiserotonin-effects.5. LSD 25 was ineffective in all concentrations used.6. Largactil and reserpin inhibit retraction in high doses. There seems to be a non specific effect caused by the high dose.7. Reserpine does not release a retraction-inducing agent from the platelets, which could be detected in the centrifuged platelet-free plasma used for the incubation.8. Serotonin does not replace the retraction-cofactor of Hartert, or the dialyzable factor of Lüscher in synthetic clotting substrates.9. Serotonin is of no essential value in inducing normal retraction of human plasma clots.

Sign in / Sign up

Export Citation Format

Share Document