Nonlocal stochastic mixing-length theory and the velocity profile in the turbulent boundary layer

Turbulence mixing by finite size eddies will be treated by means of a novel formulation of nonlocal K-theory, involving sample paths and a stochastic closure hypothesis, which implies a well defined recipe for the calculation of sampling and transition rates. The connection with the general theory of stochastic processes will be established. The...

From microscopia to macroscopia: An educated "game of chance" in physics

In this article I will make an attempt to explain the significance of probabilistic statistical mechanics and the notion of molecular chaos - from Gibbs and stochastic process (an ancient concept' now rapidly random walk of a Brownian particle. We will see how - as thermal activation. Escape

Temperature relaxation at the Kapitza-boundary-resistance paradox

The calculation of the Kapitza boundary resistance between dissimilar harmonic solids has for a long time [W. A. Little, Can. J. Phys. 37, 334 (1959)] presented a paradox: this resistance erroneously tends to a finite value in the limit of identical solids. We resolve this paradox by calculating temperature differences in the final heat...

Stochastic Theory of Turbulence Mixing by Finite Eddies in the Turbulent Boundary Layer

Turbulence mixing is treated by means of a novel formulation of nonlocal K-theory, involving sample paths and a stochastic hypothesis. The theory simplifies for mixing by exchange (strong-eddies) and is then applied to the boundary layer (involving scaling). This maps boundary layer turbulence onto a nondiffusive (Kubo-Anderson or kangaroo) type...

Studies on Aerosols in the Marine Atmospheric Surface Layer

The work performed in 1992 in the framework of the EUROTRAC subproject ASE was mainly focused on three topics. The first was the extension of the modified CLUSE numerical model [Rouault et al., 1991; De Leeuw et al., 1992a] to over-ocean conditions. The modifications in the new code (SEACLUSE) include the influence of waves on the air flow and...

Critical Dynamics: The Expansion of the Master Equation Including a Critical Point

In this thesis it is shown how to solve the master equation for a Markov process including a critical pointby means of successive approximations in terms of a small parameter.A critical point occurs if, by adjusting an externally controlled quantity, the system shows a transition from normal monostableto bistablebehaviour. Examples of the...

On the theory of ultra-short time resolved photo-detection

We discuss the theory of photo-detection with arbitrary time-resolution. In the limit of ultra-short response times, we show how in the quantal heterodyne detection process both difference and sum-frequencies occur in the detector output, contrary to what seems to be the general suggestion. The results compare with purely classical quadratic...

A theory of cooperative effects in stimulated Cerenkov radiation

In this paper the possibility of cooperative effects in Cerenkov radiation will be discussed theoretically. A crude sketch is given of a possible capture of photons from a part of the rather broadband Cerenkov spectrum in a high quality resonator. We then introduce a classical Markoffian master equation for the system, accounting for Cerenkov...

Kooperatieve verschijnselen in komplekse systemen

Koöperatíeve verschijnselen kunnen optreden in systemen die opgebouwd zíjn uít zeer vele met elkaar wisselwerkende subsystemen. Voor de 'míkroscopische' subsystemen kan men bijvoorbeeld denken aan menselijke individuen, hun hersencellen, of aan atomen. Het samengestelde, 'makroskopische' systeem kan dan respektievelijk de maatschappíj, de...

Theory of self-locking phenomena in the pressure broadened three-mode He-Ne laser

Taking account of pressure broadening the coefficients in Lamb's third-order amplitude and phase determining equations for three modes are evaluated in the Doppler limit, and comparison is made with other theories. After expanding the coefficients to first order in the detuning ε from the linecenter an expression is presented for the frequency...

Stationary momentum space solution of the Fokker-Planck equation for a simple model of a laser oscillator exhibiting spatial dispersion

Starting from a multimode hamiltonian for a system of radiating oscillators coupled with atomic reservoirs, the secular master equation for the radiation-density operator is calculated in the interaction picture after elimination of the atomic variables. Using the differential operator representation for coherent states this equation is...