scholarly journals From Interstellar Cloud to Star to Laboratory: Frontier HEDP Studies of Magnetized Colliding Plasma Flows with Strong Radiative Cooling

2020 ◽  
Author(s):  
Adam Frank ◽  
Keyword(s):  
Interstellar Cloud ◽  
Radiative Cooling ◽  
Plasma Flows

The Role of Collisionality and Radiative Cooling on the Interactions Between Supersonic Plasma Flows

2018 ◽  
Author(s):  
G. W. Collins ◽  
J. C. Valenzuela Ahumada ◽  
C.A. Speliotopoulos ◽  
N. Aybar ◽  
F. Conti ◽  
...  
Keyword(s):  
Radiative Cooling ◽  
Plasma Flows ◽  
Supersonic Plasma

Supernovae and interstellar gas dynamics

1967 ◽  
Vol 31 ◽  
pp. 117-119
Author(s):  
F. D. Kahn ◽  
L. Woltjer
Keyword(s):  
Lower Limit ◽  
High Velocity ◽  
Gas Dynamics ◽  
Interstellar Cloud ◽  
Interstellar Gas ◽  
Random Motions ◽  
Relativistic Particles

The efficiency of the transfer of energy from supernovae into interstellar cloud motions is investigated. A lower limit of about 0·002 is obtained, but values near 0·01 are more likely. Taking all uncertainties in the theory and observations into account, the energy per supernova, in the form of relativistic particles or high-velocity matter, needed to maintain the random motions in the interstellar gas is estimated as 1051·4±1ergs.

Saturation mechanism and generated viscosity in gravito-turbulent accretion disks

2020 ◽  
Vol 640 ◽  
pp. A53
Author(s):  
L. Löhnert ◽  
S. Krätschmer ◽  
A. G. Peeters
Keyword(s):  
Growth Rate ◽  
Numerical Simulations ◽  
Accretion Disks ◽  
Gravitational Instability ◽  
Turbulent Viscosity ◽  
Radial Distance ◽  
Maximum Growth ◽  
Wave Number ◽  
Radiative Cooling ◽  
Mixing Length

Here, we address the turbulent dynamics of the gravitational instability in accretion disks, retaining both radiative cooling and irradiation. Due to radiative cooling, the disk is unstable for all values of the Toomre parameter, and an accurate estimate of the maximum growth rate is derived analytically. A detailed study of the turbulent spectra shows a rapid decay with an azimuthal wave number stronger than ky−3, whereas the spectrum is more broad in the radial direction and shows a scaling in the range kx−3 to kx−2. The radial component of the radial velocity profile consists of a superposition of shocks of different heights, and is similar to that found in Burgers’ turbulence. Assuming saturation occurs through nonlinear wave steepening leading to shock formation, we developed a mixing-length model in which the typical length scale is related to the average radial distance between shocks. Furthermore, since the numerical simulations show that linear drive is necessary in order to sustain turbulence, we used the growth rate of the most unstable mode to estimate the typical timescale. The mixing-length model that was obtained agrees well with numerical simulations. The model gives an analytic expression for the turbulent viscosity as a function of the Toomre parameter and cooling time. It predicts that relevant values of α = 10−3 can be obtained in disks that have a Toomre parameter as high as Q ≈ 10.

An Experimental Multiple-Organ Model for the Study of Regional Net Release/Uptake Rates of Tissue-type Plasminogen Activator in the Intact Pig

1997 ◽  
Vol 78 (03) ◽  
pp. 1150-1156 ◽  
Author(s):  
Christina Jern ◽  
Heléne Seeman-Lodding ◽  
Bjӧrn Biber ◽  
Ola Winsӧ ◽  
Sverker Jern
Keyword(s):  
Plasminogen Activator ◽  
Multiple Organ ◽  
Tissue Type ◽  
Hepatic Veins ◽  
Plasma Flows ◽  
Tissue Type Plasminogen Activator ◽  
Type Plasminogen Activator ◽  
Uptake Rates ◽  
Net Release

SummaryExperimental data indicate large between-organs variations in rates of synthesis of tissue-type plasminogen activator (t-PA), which may reflect important differences in the capacity for constitutive and stimulated t-PA release from the vascular endothelium. In this report we describe a new multiple-organ experimental in vivo model for simultaneous determinations of net release/uptake rates of t-PA across the coronary, splanchnic, pulmonary, and hepatic vascular beds. In eleven intact anesthetized pigs, blood samples were obtained simultaneously from the proximal aorta, coronary sinus, pulmonary artery, and portal and hepatic veins. Plasma flows were monitored separately for each vascular region. Total plasma t-PA was determined by ELISA with a porcine t-PA standard. Regional net release/uptake rates were defined as the product of arteriovenous concentration gradients and local plasma flows. The net release of t-PA across the splanchnic vascular bed was very high, with a mean output of 1,919 ng total t-PA X min-1 (corresponding to 90 ng per min and 100 g tissue). The net coronary t-PA release was 68 ng X min-1 (30 ng X min-1 X 100 g"1)- Pulmonary net fluxes of t-PA were variable without any significant net t-PA release. The net hepatic uptake rate was 4,855 ng X min-1 (436 ng X min-1 X 100 g-1). Net trans-organ changes of active t-PA mirrored those of total t-PA. The results demonstrate marked regional differences in net release rates of t-PA in vivo. The experimental model we present offers new possibilities for evaluation of regional secretion patterns in the intact animal.

Probe diagnostics of laboratory and ionospheric rarefied plasma flows

2013 ◽  
Vol 19 (1(80)) ◽  
pp. 13-19
Author(s):  
V.A. Shuvalov ◽  
◽  
A.A. Lukenjuk ◽  
N.I. Pismenny ◽  
S.N. Kulagin ◽  
...  
Keyword(s):  
Plasma Flows ◽  
Probe Diagnostics

FORMATION OF Nb-CONTAINING ALLOYS IN THE SURFACE LAYER OF MATERIALS BY COMPRESSION PLASMA FLOWS

2015 ◽  
Vol 19 (2) ◽  
pp. 153-167 ◽  
Author(s):  
Nikolai Cherenda ◽  
Andrej K. Kuleshov ◽  
Vitali I. Shymanski ◽  
Vladimir V. Uglov ◽  
N. V. Bibik ◽  
...  
Keyword(s):  
Surface Layer ◽  
Plasma Flows ◽  
Compression Plasma Flows

SPECTROSCOPIC AND PROBE DIAGNOSTICS OF CARBON PLASMA FLOWS OF A PULSE VACUUM ARC

2010 ◽  
Vol 14 (1-2) ◽  
pp. 157-163 ◽  
Author(s):  
I. P. Smyaglikov ◽  
N. I. Chubrik ◽  
S.V. Goncharik ◽  
V. V. Azharonok ◽  
L. E. Krat'ko ◽  
...  
Keyword(s):  
Vacuum Arc ◽  
Plasma Flows ◽  
Probe Diagnostics ◽  
Carbon Plasma

STRUCTURE OF THE AUSTENITIC STEEL SURFACE LAYER SUBJECTED TO COMPRESSION PLASMA FLOWS IMPACT

2020 ◽  
Vol 24 (3) ◽  
pp. 211-225
Author(s):  
Nikolai N. Cherenda ◽  
Vladimir V. Uglov ◽  
Yu. V. Martinovich ◽  
I. A. Betanov ◽  
Valiantsin M. Astashynski ◽  
...  
Keyword(s):  
Surface Layer ◽  
Austenitic Steel ◽  
Steel Surface ◽  
Plasma Flows ◽  
Compression Plasma Flows
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