The gyrorelaxation damping and excitation of a helicon wave

It is shown that in the region of collisional temporal dispersion the damping of a helicon wave is primarily caused by the gyrorelaxation effect.     

Peculiarities of the helicon mode propagation with m < 0 in radially nonuniform plasma cylinder

The peculiarities of the helicon mode propagation with m < 0 along plasma cylinder with radial density gradient are analysed. It is shown that the modes with m < 0 can propagate near cylinder axis region where the effects of density gradient are not important.     

Destabilization of the m = 1 diocotron mode in non-neutral plasmas

The theory for a Penning-Malmberg trap predicts m = 1 diocotron stability. However, experiments with hollow profiles show robust exponential growth. We propose a new mechanism of destabilization of this mode, involving parallel compression due to end curvature. The results are in good agreement with the experiments. The resulting modified drift-Poisson equations are analogous to the geophysical shallow water equations, and conservation of line integrated density corresponds to that of potential vorticity. This analogy predicts Rossby waves in non-neutral plasmas and an m = 1 instability in fluids.     

Dynamical analysis of the nonlinear growth of the m = n = 1 resistive internal mode

A dynamical analysis is presented that self-consistently takes into account the motion of the critical layer, in which the magnetic field reconnects, to describe how the m=n=1 resistive internal kink mode develops in the nonlinear regime. The amplitude threshold marking the onset of strong nonlinearities due to a balance between convective and mode coupling terms is identified. We predict quantitatively the early nonlinear growth rate of the m=n=1 mode below this threshold.     

Parametric excitation of helicon and acoustic waves in piezoelectric semiconductor-plasma

The parametric excitation of a helicon and an acoustic wave in a piezoelectric semiconductor-plasma in the presence of a strong magnetic field has been investigated using the coupled mode theory. The expressions for the threshold value of the electric field required for the onset of instability and for the growth rate well above the threshold have been obtained. It is observed that an acoustic wave of higher frequency and higher phase velocity than that of the pump wave cannot be excited. The analysis has been applied to the case of n type InSb sample where the threshold value of the electric field is found to be of the order 5.2 × 10³ Vm^?1 and the growth rate at an electric field 5.2 × 10⁴ Vm^?1 is of the order of 8.7 × 10¹⁰ sec^?1.     

导出E=mc2和m=m0/1-v2√c2的一种方案

借助光子导出了E=mc2和m=(m0)/(1-v2/c2).     

CFETR螺旋波行波天线的仿真设计与分析

在中国聚变工程实验堆(CFETR)螺旋波的设计参数下,提出一种多阵列行波天线用于螺旋波电流驱动的方案.利用电磁仿真软件CST对三维天线的参考模型进行了仿真,结果表明,在50MHz带宽内,天线电压驻波比<1.2,且天线阵列激发的k谱具有很好的定域性,有利于提高天线的电流驱动效率.     

第一性原理对Al_mSi_n(m=1,2;n=1～6)团簇结构与性质的研究

本文运用第一性原理对Al_mSi_n（m=1,2;n=1～6）团簇的结构与性质进行了研究.在BLYP的水平上进行了结构优化和频率分析,得到了团簇的最低能量结构.同时计算和讨论了A1_msi_n团簇的束缚能、总能的二阶能量差分和分裂能以及费米能随原子数的变化.研究结果表明:Al_mSi_n团簇在m+n<4时的几何结构是平面结构,从4个原子开始转为空间的立体结构;除AlSi₃和Al₂Si₂团簇外,Al_mSi_n（m=1,2;n=1～6）团簇的束缚能随原子数增加而减小;分析A1_mSi_n（m=1,2;n=1～6）团簇的二阶能量差分和分裂能发现:在m+n=3,5时,团簇都出现较稳定的结构.     

轴对称环状静电模的漂移波湍流参量激发理论研究

本文所论述的轴对称环状静电模是指环形磁约束等离子体(如托卡马克)中环向模数为零的近理想静电流体模,它包含有测地声模和基频率与之较低的声模;也含有所谓的‘近零频带状流’.本文根据冷离子流体模型在圆形磁面构成的准环坐标系中的表示,对涉及以上三种模式的漂移波湍流参量激发理论,在一级环形效应近似下,进行了系统讨论,并证明了带状流的四个新命题.利用对漂移波能谱的参数化描写,注意到由漂移波能谱径向有限宽度所引发的特性,如波能传播量的双Landau奇点,揭示了有限宽度对径向δ谱所得结果的重要修正:如,对近零频带状流和测地声模的参量激发条件带来的严格限制.此外,还讨论了密度带状流在高q条件下被激发的可能性.本文选用合理的物理参数.采用图示方法详细地讨论了有关的数值结果.分析表明,测地声模和近零频带状流的参量激发不可能发生在同一小半径处;如果测地声模被参量激发,也应能观察到密度带状流.     

Electrostatic mode excitation in electron holes due to wave bounce resonances

A kinetic theory of resonant interaction between electrostatic waves and the bounce motion of electrostatically trapped electrons is developed. Precise criteria are derived for the stability of electrostatic potential structures which trap electrons in a highly magnetized plasma. The theory explains the energy transfer from electron phase space holes to waves observed in simulations. It may also account for the destabilization of electrostatic waves propagating obliquely to the geomagnetic field and some characteristics of the holes as observed in the auroral ionosphere.     

Electronic structure and infrared spectrum of a WnC0＇± （n= 1-6） cluster

W_nC^0,± (n=1-6) clusters are investigated by using the density functional theory (DFT) at the B3LYP/LANL2DZ level. We find that the neutral, anionic and cationic ground state structures are similar within the same size, and constituted by substituting a C atom for one W atom in the structures of W_n+1 clusters. The natural bond orbital (NBO) charge analyses indicate that the direction of electron transfer is from the W atom to the 2p orbital of the C atom. In addition, the calculated infrared spectra of the W_nC^0,± (n=2-6) clusters manifest that the vibrational frequencies of neutral, anionic and cationic clusters are similar in a range of 80 cm^-1-864 cm^-1. The high frequency, strong peak modes are found to be an almost stretched deformation of the carbide atom. Finally, the polarizabilities of W_nC^0,± (n=1-6) clusters are also discussed.     

(AlB2)m (m=1~6) 团簇的几何结构和电子性质

采用密度泛函理论(DFT)中的B3LYP方法得到了(AlB2)m团簇的平衡几何结构. 计算并分析了基态掺杂团簇的平均结合能、电离势、能隙和前线分子轨道. 结果表明：掺杂团簇(AlB2)m (m=1~6)整体上具有较高化学活性,(AlB2)5团簇具有金属特征. Al原子总是向团簇外围扩散并且以配位数较少的方式与主团簇结合,团簇表现出以AlB2分子为基元生长的迹象. B-Al键长大于B-B键长. 电荷总是从Al原子转移到B原子. (AlB2)m团簇中B原子的2p轨道在成键中起主要作用,并使(AlB2)m团簇趋于形成离域π键.     

Studies of the pyrazine-bridged antiferromagnets Fe(pyz)mX2 (m=1, X=CF3SO3 −, NCO−; m=2, X=NCS−)

Mössbauer and magnetic susceptibility data are reported for the title complexes. The data demonstrate that these pyrazine-bridged complexes represent examples of low-dimensional lattices with anisotropic magnetic exchange arising from different interaction strengths of the bridging ligands.     

导出E=mc~2和m=m_0/(1-v~2/c~2)~(1/2)的一种方案

借助光子导出了E=mc2和m=m01-v2/c2.