Long time asymptotics of the totally asymmetric simple exclusion process

We study the long time asymptotics of the relaxation dynamics of the totally asymmetric simple exclusion process on a ring. Evaluating the asymptotic amplitudes of the local currents by the algebraic Bethe ansatz method, we find the relaxation times starting from the step and alternating initial conditions are governed by different eigenvalues of the Markov matrix. In both cases, the scaling exponents of the leading asymptotic amplitudes with respect to the total number of sites are found to be -1. We also study the asymptotics of correlation functions such as the emptiness formation probability.Comment: 21 pages, 5 figures, revised versio

Prompt particle acceleration around moving X-point magnetic field during impulsive phase of solar flares

We present a model for high-energy solar flares to explain prompt proton and electron acceleration, which occurs around moving X-point magnetic field during the implosion phase of the current sheet. We derive the electromagnetic fields during the strong implosion phase of the current sheets, which is driven by the converging flow derived from the magnetohydrodynamic equations. It is shown that both protons and electrons can be promptly (within 1 second) accelerated to approximately 70 MeV and approximately 200 MeV, respectively. This acceleration mechanism can be applicable for the impulsive phase of the gradual gamma ray and proton flares (gradual GR/P flare), which have been called two-ribbon flares

3次元X型電流ループ合体による高エネルギーフレア爆発

The coronal explosion, discovered by De Jager and Boelee (1984), and interpreted by them as manifestations of plasma streaming out of the flare kernels, can also be interpreted as signatures of current loop coalesscence in the flaring region

Triangle singularity enhancing isospin violation in Bˉs0→J/ψπ0f0(980)\bar B_s^0 \to J/\psi \pi^0 f_0(980)

We perform calculations for the $\bar B_s^0 \to J/\psi \pi^0 f_0(980)$ and $\bar B_s^0 \to J/\psi \pi^0 a_0(980)$ reactions, showing that the first one is isospin-suppressed while the second one is isospin-allowed. The reaction proceeds via a triangle mechanism, with $\bar B_s^0 \to J/\psi K^* \bar K +c.c.$, followed by the decay $K^* \to K\pi$ and a further fusion of $K\bar K$ into the $f_0(980)$ or $a_0(980)$. We show that the mechanism develops a singularity around the $\pi^0 f_0(980)$ or $\pi^0 a_0(980)$ invariant mass of 1420 MeV where the $\pi^0 f_0$ and $\pi^0 a_0$ decay modes are magnified and also the ratio of $\pi^0 f_0$ to $\pi^0 a_0$ production. Using experimental information for the $\bar B_s^0 \to J/\psi K^* \bar K +c.c.$ decay, we are able to obtain absolute values for the reactions studied which fall into the experimentally accessible range. The reactions proposed and the observables evaluated, when contrasted with actual experiments should be very valuable to obtain information on the nature of the low lying scalar mesons.Comment: 19 pages, 9 figures; V2: improved discussions in sections II and III, version to appear in Chin. Phys.

太陽紅炎の形成及び振動の動的モデル

We investigate a dynamical model of prominence formation in a current sheet at the boundary between two regions of opposite magnetic polarity. Coupled nonlinear equations describing the temporal compression and condensation of plasma in the current sheet are set up as a natural extension of the usual equations for current sheet collapse (Imshennik and Syrovatskii, 1967). It is shown that under certain conditions the current sheet undergoes a nonlinear oscillation during the compression. The thermal instability with cooling is driven by a density enhancement produced during the current sheet formation stage

太陽フレアにおける電流ループ合体を示すコロナ爆発

We present a model for high-energy solar flare explosions driven by 3-dimensional X-type current loop coalescence. The 3-dimensional X-type loop coalescence, where two crossed fluxtubes interact in one point, is a fundamentally new process as compared to the 1-D and 2-D cases studied earlier. It is shown that, following the strong plasma collapse due to pinch effect, a point-like plasma explosion can be driven and also fast magnetosonic shock waves can be excited;We found that the conditions in the area producing the remarkable flare bursts of 21 May 1984 were indeed such that the many flare spikes could have been due to 3-D explosive X-type current loop coalescence. We also show, by studing the conding the conditions of shock formation in a Gamma ray flare, that the time delay of γ-rays from the impulsive phase could be the time needed for the shock formation in the flaring region.We draw some general conclusions on the question why certain flares do emit γ-rays in the Mev energy range, and why other, apparently important and large flares, do not. We accentuate the fact that a well-developed high-energy flare has three phases of particle acceleration

小さい高エネルギーフレアにおけるX型電流ループ合体による粒子加速

We studied the acceleration conditions in the small but fairly energetic flare of May 21, 1984 at 13:26 UT. The most pronounced aspect of this flare was a series of 13 microwave / x-ray spikes, each lasting for about 0.1s. A previous study has shown that each of these was due to a series of successive sudden formations of small plasma knots of high energy particles. Each of these knots lost its energy in about 50 ms. In the present study we show that these knots can originate by the process of x-type (3-D) flux tube coalescence. The predicted rise time (30 to 50 ms) and energy are in good agreement with the observationally derived parameters

太陽の捩じれた磁気ループでのリング状のエネルギー解放

We investigate the magnetohydrodynamic (MHD) instability of the magnetic loop in association with the solar flare. We use \u27safety factor\u27 q to describe the local twist of the magnetic loop where low q value means the strong twist, then it becomes more unstable for the MHD instability.We present the q profile on the equilibrium for two types which may correspond to small and large flare. One type corresponding to small flare is the slim cylindrical untwisted magnetic loop in initial stage. When the tube is twisted, low q region is localized around the axis of the center of the loop. We conclude that the localized low q region must be ring shaped. The energy release by MHD instability can be localized with the ring shaped region. The other type is barrel shaped untwisted magnetic loop which may correspond to the large flare. After the twist, low q region is wide along the axis. The MHD instability is caused on the whole magnetic loop, therefore the energy release is global

磁気島の爆発的合体過程の粒子加速

An explosive reconnection process associated with the nonlinear evolution of the coalescence instability is found through studies of the electromagnetic particle simulation. The explosive coalescence is a process of magnetic collapse, in which we find the magnetic and electrostatic field energies and temperatures (ion temperature in the coalescing direction, in particular) explode toward the explosion time to as (t_0 - t)^, (t_0 - t)^, and (t_0 - t)^, respectively.Single-peak, double-peak, and triple-peak structures of magnetic energy, temperature, and electrostatic energy, respectively, are observed on the simulatton as overshoot amplitude oscillations and these features are theoretically explained. Rapid acceleration of particles binormal to the magnetic field and electric field becomes possible