Phase dynamics of a relativistic electron excited by the potential field of a wave packet: Reconstruction of phase space

1998 ◽  
Vol 41 (5) ◽  
pp. 442-446
Author(s):  
A. S. Krotov ◽  
A. A. Tel’nikhin

1. The Statistics of a Degenerate Gas . An interesting application of the new statistics of Fermi and Dirac has been made by Thomas (and also independently by Fermi) to the distribution of electrons in heavy atoms. The basic idea of these researches is that the “electron gas” surrounding a nuclues “degenerate,” so that every cell of extension h 3 of a six dimensional phase space contains two electrons, one electron spinning in one direction and another in the opposite direction. An upper limit to the possible translational energies of the electrons is imposed by the condition that electrons shall not have enough energy to escape from the field of the nucleus, viz:— ϵ≼ e . V, (1) where ϵ and e represent the energy and charge of the electron and V is the potential field. The possible range of momentum co-ordinates (neglecting relativity considerations) is then limited by p ≼(2 me V) ½ (2) and the total number of cells of extension h 3 in the phase space is given by 4π(2 me V) 3/2 /3 h 3 (3) for every unit of ordinary (co-ordinate) space available. If every cell contains two electrons, the density is given by ρ = —8π e (2 me V) 3/2 /3 h 3 . (4) Since, however, the potential V is determined by the nuclear charge and the distribution of electrons, we have ∇ 2 = —4πρ = (32π 2 e (2 me V) 3/2 /3 h 3 ,(5) an equation to determine V, subject to V → 0 as r → ∞ V r as r → 0}, (6) where E is the charge on the nucleus.





Author(s):  
David Chelidze ◽  
Ming Liu

This paper considers a dynamical system subjected to damage evolution in variable operating conditions to illustrate the reconstruction of slow-time (damage) dynamics using fast-time (vibration) measurements. Working in the reconstructed fast-time phase space, phase space warping-based feature vectors are constructed for slow-time damage identification. A subspace of the feature space corresponding to the changes in the operating conditions is identified by applying smooth orthogonal decomposition (SOD) to the initial set of feature vectors. Damage trajectory is then reconstructed by applying SOD to the feature subspace not related to the changes in the operating conditions. The theory is validated experimentally using a vibrating beam, with a variable nonlinear potential field, subjected to fatigue damage. It is shown that the changes in the operating condition (or the potential field) can be successfully separated from the changes caused by damage (or fatigue) accumulation and SOD can identify the slow-time damage trajectory.



1990 ◽  
Vol 142 (3) ◽  
pp. 345-359 ◽  
Author(s):  
S.C. Farantos ◽  
M. Founargiotakis




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