Nonlinear dynamics of beta induced Alfv\'en eigenmode driven by energetic particles

Nonlinear saturation of beta induced Alfv\'en eigenmode, driven by slowing down energetic particles via transit resonance, is investigated by the nonlinear hybrid magnetohyrodynamic gyro-kinetic code (XHMGC). Saturation is characterized by frequency chirping and symmetry breaking between co- and counter-passing particles, which can be understood as the the evidence of resonance-detuning. The scaling of the saturation amplitude with the growth rate is also demonstrated to be consistent with radial resonance detuning due to the radial non-uniformity and mode structure

Undamped electrostatic plasma waves

Electrostatic waves in a collision-free unmagnetized plasma of electrons with fixed ions are investigated for electron equilibrium velocity distribution functions that deviate slightly from Maxwellian. Of interest are undamped waves that are the small amplitude limit of nonlinear excitations, such as electron acoustic waves (EAWs). A deviation consisting of a small plateau, a region with zero velocity derivative over a width that is a very small fraction of the electron thermal speed, is shown to give rise to new undamped modes, which here are named {\it corner modes}. The presence of the plateau turns off Landau damping and allows oscillations with phase speeds within the plateau. These undamped waves are obtained in a wide region of the $(k,\omega_{_R})$ plane ($\omega_{_R}$ being the real part of the wave frequency and $k$ the wavenumber), away from the well-known `thumb curve' for Langmuir waves and EAWs based on the Maxwellian. Results of nonlinear Vlasov-Poisson simulations that corroborate the existence of these modes are described. It is also shown that deviations caused by fattening the tail of the distribution shift roots off of the thumb curve toward lower $k$-values and chopping the tail shifts them toward higher $k$-values. In addition, a rule of thumb is obtained for assessing how the existence of a plateau shifts roots off of the thumb curve. Suggestions are made for interpreting experimental observations of electrostatic waves, such as recent ones in nonneutral plasmas.Comment: 11 pages, 10 figure

Competitive complex of machinery and technologies for the production of grain and feed

The current situation in agricultural production is challenging. During the last 2 decades, the agrarian production system has been deteriorating. It concerns crop rotations, moisture accumulation and moisture conservation technologies, ways of increasing soil fertility and growing environmentally friendly grain, reducing production costs and increasing product profitability. But there are forced late sowings and artificial “drought”. All this provides reasons to consider domestic breeding and seed production obsolete and to introduce the foreign analogue, which has planned negative impacts not only on quantitative, but also on qualitative safety. The article provides the solution to this major strategic problem. Under the research program of the Russian Academy of Agricultural Sciences, a highly competitive technology for the production of grain and fodder was developed on the basis of only domestic equipment that 2-5 times predominates over the best foreign analogues in functional indicators. It was confirmed by a number of state tests in 1990-2016 and approved by numerous meetings of the Scientific and Technical Council of the Ministry of Agriculture of the Russian Federation, RAS. The units of domestic tractors and functional machines that can compete with the best foreign counterparts have been developed

Criticality in a Vlasov-Poisson system - a fermionic universality class

A model Vlasov--Poisson system is simulated close the point of marginal stability, thus assuming only the wave-particle resonant interactions are responsible for saturation, and shown to obey the power--law scaling of a second-order phase transition. The set of critical exponents analogous to those of the Ising universality class is calculated and shown to obey the Widom and Rushbrooke scaling and Josephson's hyperscaling relations at the formal dimensionality $d=5$ below the critical point at nonzero order parameter. However, the two-point correlation function does not correspond to the propagator of Euclidean quantum field theory, which is the Gaussian model for the Ising universality class. Instead it corresponds to the propagator for the fermionic {\it vector} field and to the {\it upper critical dimensionality} $d_c=2$. This suggests criticality of collisionless Vlasov-Poisson systems as representative of the {\it universality class} of critical phenomena of {\it a fermionic} quantum field description.Comment: 10 pages, 6 figures, Submitted to Phys. Rev.