We theoretically investigate the interaction and propagation characteristics of two co/counter propagating Mach cones triggered by two projectile particles moving with supersonic velocities in the same/opposite directions through a dusty plasma medium. The Mach cone solutions are obtained by solving a model set of fluid equations for a heavily charged dust fluid that includes the contributions of the projectile particles in the Poisson equation. The density profiles and velocity vector maps of the Mach wings show interesting structural changes when they interact with each other and form patterns similar to interference fringes. Compared to the co-propagating Mach cones, the wings of counter propagating Mach cones produce a larger number of maxima and minima in the pattern resulting from their mutual interaction. In addition the time duration of the formation of two maxima or minima at a particular point decreases due to the interactions of Mach cones. Another notable feature is that the spacing between adjacent maxima increases while the fringe angle decreases with the increase of relative velocity of the counter propagating projectile particles.
DustNET: enabling machine learning and AI models of dusty plasmas
Los Alamos National Laboratory（洛斯阿拉莫斯国家实验室）；Justus Liebig University（吉森大学）；THM University of Applied Sciences（THM应用科学大学）；Soochow University（苏州大学）；Donghua University（东华大学）；Emory University（埃默里大学）；University of Michigan（密歇根大学）
Dust ion acoustic solitary structures in nonthermal dusty plasma
研究了由负电荷尘埃粒子、绝热正离子和非热电子组成的非磁化非热等离子体中尘埃离子声孤波结构。对于等温电子，目前的等离子体系统不支持任何双电层解决方案，而对于非热电子，负电位双电层开始出现时，非热参数超过一个临界值。然而，这种双层解并不能限制本系统所有负势孤立波的出现。结果表明，两种不同类型的负势孤波的出现受到M_c<M<M_D whereas the second type solitary wave exists for all M>_D的限制，其中M_c为马赫数M的下限，M_D（>M_c）为负势双层对应的马赫数。在M=M_D-ε_1和M=M_D+ε_2处，观察到孤波负势振幅之间的有限跳跃，其中0<ε_1<M_D-M_c和ε_2>0。提出了双电层存在的解析理论。还提供了一个数值方案，以找出存在双层解时的马赫数值以及该双层的振幅。虽然两极孤波共存的发生受到M_c<M <= M_max的限制，但当M>M_max时，仍然只存在负势孤波，这里M_max是只存在正势孤波时M的上界。发现了反映能量积分孤立子结构性质的不同组分参数空间，这些解空间为孤立子结构的形成提供了新的结果和物理思想。
