Gluon Field Strength Correlation Functions within a Constrained Instanton Model

We suggest a constrained instanton (CI) solution in the physical QCD vacuum which is described by large-scale vacuum field fluctuations. This solution decays exponentially at large distances. It is stable only if the interaction of the instanton with the background vacuum field is small and additional constraints are introduced. The CI solution is explicitly constructed in the ansatz form, and the two-point vacuum correlator of gluon field strengths is calculated in the framework of the effective instanton vacuum model. At small distances the results are qualitatively similar to the single instanton (SI) case, in particular, the form factor $D_{1}$ is small, which is in agreement with the lattice calculations.Comment: 25 pages (RevTex), 7 ps figures; some references added, one figure replace

MILITARY PROGRESS IN A GLOBAL WORLD: THE NEED FOR A PROFESSIONAL APPROACH TO THE ETERNAL PROBLEMS

The author stresses that military progress is a part of the social progress, therefore its analysis involves the understanding of common problems and criteria of the development of mankind at this or that stage of history. The article covers new trends characterizing the military progress of the modern world. In particular, peculiarities of military progress after the «cold war», after the abolition of bipolar world system are analyzed. However, the real aims are the same, although they assume more rational nuance.Автор подчеркивает, что военный прогресс представляет собой часть общественного прогресса, поэтому его анализ предполагает понимание общих проблем и критериев развития человечества на том или ином историческом этапе. В статье освещаются новые тенденции, характеризующие военный прогресс современности. В частности, анализируются особенности военного прогресса после «холодной войны», после упразднения мировой биполярной системы. Тем не менее, реальные цели при этом остаются прежними, хотя и приобрели более рациональную окраску

How much laser power can propagate through fusion plasma?

Propagation of intense laser beams is crucial for inertial confinement fusion, which requires precise beam control to achieve the compression and heating necessary to ignite the fusion reaction. The National Ignition Facility (NIF), where fusion will be attempted, is now under construction. Control of intense beam propagation may be ruined by laser beam self-focusing. We have identified the maximum laser beam power that can propagate through fusion plasma without significant self-focusing and have found excellent agreement with recent experimental data, and suggest a way to increase that maximum by appropriate choice of plasma composition with implication for NIF designs. Our theory also leads to the prediction of anti-correlation between beam spray and backscatter and suggests the indirect control of backscatter through manipulation of plasma ionization state or acoustic damping.Comment: 15 pages, 4 figures, submitted to Plasma Physics and Controlled Fusio

Multilevel Analysis of Oscillation Motions in Active Regions of the Sun

We present a new method that combines the results of an oscillation study made in optical and radio observations. The optical spectral measurements in photospheric and chromospheric lines of the line-of-sight velocity were carried out at the Sayan Solar Observatory. The radio maps of the Sun were obtained with the Nobeyama Radioheliograph at 1.76 cm. Radio sources associated with the sunspots were analyzed to study the oscillation processes in the chromosphere-corona transition region in the layer with magnetic field B=2000 G. A high level of instability of the oscillations in the optical and radio data was found. We used a wavelet analysis for the spectra. The best similarities of the spectra of oscillations obtained by the two methods were detected in the three-minute oscillations inside the sunspot umbra for the dates when the active regions were situated near the center of the solar disk. A comparison of the wavelet spectra for optical and radio observations showed a time delay of about 50 seconds of the radio results with respect to optical ones. This implies a MHD wave traveling upward inside the umbral magnetic tube of the sunspot. Besides three-minute and five-minute ones, oscillations with longer periods (8 and 15 minutes) were detected in optical and radio records.Comment: 17 pages, 9 figures, accepted to Solar Physics (18 Jan 2011). The final publication is available at http://www.springerlink.co