Excitation of zonal flow by the modulational instability in electron temperature gradient driven turbulence

The generation of large-scale zonal flows by small-scale electrostatic drift waves in electron temperature gradient(ETG) driven turbulence model is considered. The generation mechanism is based on the modulational instability of a finite amplitude monochromatic drift wave. The threshold and growth rate of the instability as well as the optimal spatial scale of zonal flow are obtained.Comment: 10 pages, 3 figure

Experiment on suppression of spontaneous undulator radiation at ATF

We propose undertaking a demonstration experiment on suppressing spontaneous undulator radiation from an electron beam at BNL's Accelerator Test Facility (ATF). We describe the method, the proposed layout, and a possible schedule. There are several advantages in strongly suppressing shot noise in the electron beam, and the corresponding spontaneous radiation. The self-amplified spontaneous (SASE) emission originating from shot noise in the electron beam is the main source of noise in high-gain FEL amplifiers. It may negatively affect several HG FEL applications ranging from single- to multi-stage HGHG FELs. SASE saturation also imposes a fundamental hard limit on the gain of an FEL amplifier in a coherent electron-cooling scheme. A novel active method for suppressing shot noise in relativistic electron beams by many orders-of-magnitude was recently proposed. While theoretically such strong suppression appears feasible, the performance and applicability of this novel method must be evaluated experimentally. Several practical questions about the proposed noise suppressor, such as 3D effects and/or sensitivity to the e-beam parameters also require experimental clarification. To do this, we propose here a proof-of-principle experiment using elements of the VISA FEL at BNL's Accelerator Test Facility

Two-dimensional nonlinear vector states in Bose-Einstein condensates

Two-dimensional (2D) vector matter waves in the form of soliton-vortex and vortex-vortex pairs are investigated for the case of attractive intracomponent interaction in two-component Bose-Einstein condensates. Both attractive and repulsive intercomponent interactions are considered. By means of a linear stability analysis we show that soliton-vortex pairs can be stable in some regions of parameters while vortex-vortex pairs turn out to be always unstable. The results are confirmed by direct numerical simulations of the 2D coupled Gross-Pitaevskii equations.Comment: 6 pages, 9 figure

Theoretical and Methodological Support for the Regional Development Strategy of Ukraine

The paper notes that one of the current priorities of Ukraine’s regional policy is to identify regional development problems and implement measures to solve them. At the same time, the actual absence of particular ways, both theoretical and practical, for addressing these problems, the outdated regulatory framework significantly limit the ability to comprehensively consider the wide range of issues related to regional development in Ukraine. In the course of the research, theoretical bases are generalized, and methodological support for the regional development strategy of Ukraine is developed. It is pointed out that today the strategic planning of regional development in our country is only being formed. Unfortunately, the practices and experience of European Union countries are not fully taken into account, there is no sufficient theoretical and methodological support for strategic planning of the development of territories, and the regulatory support for this process is being improved very slowly. It is established that a very important condition for the implementation of the regional development strategy is coordination and concurrence of actions of all subjects in the regional economic space – business and government of all levels – and the unification of all the positions necessary for strategic planning based on reliable information about their intentions. It is concluded that the current system of strategic planning, unfortunately, does not ensure the coherence of the macroeconomic, regional and sectoral aspect. In this regard, there is a need to improve the management system at the regional level, which should occur through reforming the public administration system and the development of local self-government as the most priority area for the implementation of public policy. The study confirms the practicality of searching for new approaches to achieve an effective formation and implementation of the regional development strategy to solve problems of territorial development, taking into account the positive experience of other countries, especially regarding measures aimed at reducing territorial imbalances, creating regional industry complexes and stimulating their development