scholarly journals Homogenisation for anisotropic kinetic random motions

2020 ◽  
Vol 25 (0) ◽  
Author(s):  
Pierre Perruchaud
Keyword(s):  
Random Motions

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.

Many splendored things: Sexuality, playfulness and play

Sexualities ◽  
2017 ◽  
Vol 21 (4) ◽  
pp. 537-551 ◽  
Author(s):  
Susanna Paasonen
Keyword(s):  
Queer Studies ◽  
Theoretical Argument ◽  
Sexual Activities ◽  
Pleasurable Activity ◽  
Random Motions

This article makes a theoretical argument for the productivity of the notions of playfulness and play in feminist and queer studies of sexuality. Defined as a mode of sensory openness and drive towards improvisation, playfulness can be seen as central to a range of sexual activities from fumbling, random motions to elaborate, rehearsed scenarios. Play in the realm of sexuality involves experimentations with what bodies can feel and do. As pleasurable activity practised for its own sake, play involves the exploration of different bodily capacities, appetites, orientations and connections. Understood in this vein, play is not the opposite of seriousness or simply synonymous with fun. Driven by the quest for bodily pleasure, play may just as well be strained, dark and hurtful in the forms that it takes and the sensory intensities that it engenders. This article argues that the mode of playfulness and acts of play allow for pushing previously perceived and imagined horizons of embodied potentiality in terms of sexual routines and identifications alike. It examines the productive avenues that the notions of playfulness and play open up in conceptualising the urgency of sexual pleasures, the contingency of desires and their congealment in categories of identity.

Bose-Einstein-type statistics, order statistics and planar random motions with three directions

2004 ◽  
Vol 36 (3) ◽  
pp. 937-970 ◽  
Author(s):  
S. Leorato ◽  
E. Orsingher
Keyword(s):  
Partial Differential Equations ◽  
Order Statistics ◽  
Constant Velocity ◽  
Uniform Motion ◽  
Change Of Direction ◽  
Telegraph Process ◽  
Cyclic Motion ◽  
Different Types ◽  
Random Motions ◽  
Bose Einstein

In this paper we study different types of planar random motions (performed with constant velocity) with three directions, defined by the vectors dj = (cos(2πj/3), sin(2πj/3)) for j = 0, 1, 2, changing at Poisson-paced times. We examine the cyclic motion (where the change of direction is deterministic), the completely uniform motion (where at each Poisson event each direction can be taken with probability ) and the symmetrically deviating case (where the particle can choose all directions except that taken before the Poisson event). For each of the above random motions we derive the explicit distribution of the position of the particle, by using an approach based on order statistics. We prove that the densities obtained are solutions of the partial differential equations governing the processes. We are also able to give the explicit distributions on the boundary and, for the case of the symmetrically deviating motion, we can write it as the distribution of a telegraph process. For the symmetrically deviating motion we use a generalization of the Bose-Einstein statistics in order to determine the distribution of the triple (N0, N1, N2) (conditional on N(t) = k, with N0 + N1 + N2 = N(t) + 1, where N(t) is the number of Poisson events in [0, t]), where Nj denotes the number of times the direction dj (j = 0, 1, 2) is taken. Possible extensions to four directions or more are briefly considered.

Kinetic description of electromagnetic fluctuations in a plasma with fluid-like random motions

1996 ◽  
Vol 228 (1-2) ◽  
pp. 125-131
Author(s):  
A.G. Sitenko ◽  
A.G. Zagorodny ◽  
P. Schram
Keyword(s):  
Kinetic Description ◽  
Random Motions

Random Motions in Markov and Semi‐Markov Random Environments 2

2021 ◽  
Author(s):  
Anatoliy Pogorui ◽  
Anatoliy Swishchuk ◽  
Ramón M. Rodríguez‐Dagnino
Keyword(s):  
Random Environments ◽  
Markov Random ◽  
Random Motions

Bose-Einstein-type statistics, order statistics and planar random motions with three directions

2004 ◽  
Vol 36 (03) ◽  
pp. 937-970 ◽  
Author(s):  
S. Leorato ◽  
E. Orsingher
Keyword(s):  
Partial Differential Equations ◽  
Order Statistics ◽  
Constant Velocity ◽  
Uniform Motion ◽  
Change Of Direction ◽  
Telegraph Process ◽  
Cyclic Motion ◽  
Different Types ◽  
Random Motions ◽  
Bose Einstein

In this paper we study different types of planar random motions (performed with constant velocity) with three directions, defined by the vectorsdj= (cos(2πj/3), sin(2πj/3)) forj= 0, 1, 2, changing at Poisson-paced times. We examine the cyclic motion (where the change of direction is deterministic), the completely uniform motion (where at each Poisson event each direction can be taken with probability) and the symmetrically deviating case (where the particle can choose all directions except that taken before the Poisson event). For each of the above random motions we derive the explicit distribution of the position of the particle, by using an approach based on order statistics. We prove that the densities obtained are solutions of the partial differential equations governing the processes. We are also able to give the explicit distributions on the boundary and, for the case of the symmetrically deviating motion, we can write it as the distribution of a telegraph process. For the symmetrically deviating motion we use a generalization of the Bose-Einstein statistics in order to determine the distribution of the triple (N0,N1,N2) (conditional onN(t) =k, withN0+N1+N2=N(t) + 1, whereN(t) is the number of Poisson events in [0,t]), whereNjdenotes the number of times the directiondj(j= 0, 1, 2) is taken. Possible extensions to four directions or more are briefly considered.

scholarly journals The Chromospheric Spectrum and the Atmosphere of 31 Cygni

1957 ◽  
Vol 3 ◽  
pp. 165-172
Author(s):  
A. McKellar ◽  
R. M. Petrie
Keyword(s):  
Ordinary Sense ◽  
Late Type ◽  
Double Stars ◽  
Random Motions ◽  
Type Giant

The binary 31 Cygni is not, in the ordinary sense, an unstable star. Nevertheless, the organizers of this symposium have invited the present paper as a discussion of additional recent evidence of random motions of masses of gas in the atmospheres of the late-type giant components of certain double stars.

scholarly journals Excitation of decay-less transverse oscillations of coronal loops by random motions

2020 ◽  
Vol 633 ◽  
pp. L8 ◽  
Author(s):  
A. N. Afanasyev ◽  
T. Van Doorsselaere ◽  
V. M. Nakariakov
Keyword(s):  
Broad Band ◽  
Random Excitation ◽  
Forced Oscillations ◽  
Oscillatory Process ◽  
Coronal Loops ◽  
Alternative Mechanism ◽  
Steady Flows ◽  
Kink Waves ◽  
Random Motions ◽  
Transverse Oscillations

Context. The relatively large-amplitude decaying regime of transverse oscillations of coronal loops has been known for two decades and has been interpreted in terms of magnetohydrodynamic kink modes of cylindrical plasma waveguides. In this regime oscillations decay in several cycles. Recent observational analysis has revealed so-called decay-less, small-amplitude oscillations, in which a multi-harmonic structure has been detected. Several models have been proposed to explain these oscillations. In particular, decay-less oscillations have been described in terms of standing kink waves driven with continuous mono-periodic motions of loop footpoints, in terms of a simple oscillator model of forced oscillations due to harmonic external force, and as a self-oscillatory process due to the interaction of a loop with quasi-steady flows. However, an alternative mechanism is needed to explain the simultaneous excitation of several longitudinal harmonics of the oscillation. Aims. We study the mechanism of random excitation of decay-less transverse oscillations of coronal loops. Methods. With a spatially one-dimensional and time-dependent analytical model taking into account effects of the wave damping and kink speed variation along the loop, we considered transverse loop oscillations driven by random motions of footpoints. The footpoint motions were modelled by broad-band coloured noise. Results. We found the excitation of loop eigenmodes and analysed their frequency ratios as well as the spatial structure of the oscillations along the loop. The obtained results successfully reproduce the observed properties of decay-less oscillations. In particular, excitation of eigenmodes of a loop as a resonator can explain the observed quasi-monochromatic nature of decay-less oscillations and the generation of multiple harmonics detected recently. Conclusions. We propose a mechanism that can interpret decay-less transverse oscillations of coronal loops in terms of kink waves randomly driven at the loop footpoints.

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