Idealized Study of a Static Electrical Field on Charged Saltating Snow Particles-猫眼课题宝

DOI：

10.3389/feart.2022.880466

发表时间：

2022-06

期刊：

影响因子：

通讯作者：

中科院分区：

其他

文献类型：

作者：

Hong-xiang Yu;Guang Li;Ning Huang;M. Lehning

在漂雪和吹雪过程中，观测到接近地表的强电场，其值可达数十千伏/米。电荷分离会显著影响粒子的运动。虽然一些研究试图阐明电荷分离的机制和由此产生的电场结构，但很少有研究关注带电对粒子轨迹的影响，这可能会影响输运机制。在这项工作中，我们通过求解中性大气边界层中的运动方程，研究了单个带电粒子在理想静电场中的轨迹。结果表明，当摩擦速度较小时，带负电粒子的跃迁高度较低，而带正电粒子的跳跃高度较高。当回弹速度开始主导垂直加速度时，这种效应对于较高的摩擦速度是相反的。我们发现了一些区域，在这些区域中，电荷分离导致粒子悬浮在地面附近。这种跃迁-悬浮转变的阈值条件与带电粒子的反弹速度和荷质比有关。我们的研究是朝着更好地理解电荷分离对漂雪的影响迈出的第一步，应该会导致在最新的跃迁模型中考虑这种影响。

Strong electric fields, with values of tens kV/m near the surface, are observed during drifting and blowing snow events. Charge separation can significantly affect particle motion. Although several investigations attempted to shed light on the mechanisms of charge separation and the resulting electric field structure, few studies paid attention to the effect of electrification on the particle trajectory, which may influence the transport mechanism. In this work, we studied trajectories of individual, charged particles in an idealized static electrical field by solving the equations of motion in a neutral atmospheric boundary layer. The results show that negatively charged particles have a lower saltation height while positively charged particles jump higher as long as friction velocities are small. This effect reverses for higher friction velocities as rebound velocities start to dominate over vertical acceleration. We find regimes, in which charge separation leads to suspension of particles close to the ground. The threshold condition for this saltation-suspension transition is related to the rebound velocity and charge-to-mass ratio of the charged particle. Our study is a first step towards a better understanding on the influence of charge separation on drifting snow and should lead to include this effect in state of the art saltation models.

Idealized Study of a Static Electrical Field on Charged Saltating Snow Particles

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