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首页> 外文期刊>Journal of Geophysical Research, A. Space Physics: JGR >Spatially Resolved Neutral Wind Response Times During High Geomagnetic Activity Above Svalbard
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Spatially Resolved Neutral Wind Response Times During High Geomagnetic Activity Above Svalbard

机译：空间解决中性风响应时间在高地磁活动期间在斯瓦尔巴特群岛

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摘要

It has previously been shown that in the high-latitude thermosphere, sudden changes in plasma velocity (such as those due to changes in interplanetary magnetic field) are not immediately propagated into the neutral gas via the ion-drag force. This is due to the neutral particles (O, O_2, and N_2) constituting the bulk mass of the thermospheric altitude range and thus holding on to residual inertia from a previous level of geomagnetic forcing. This means that consistent forcing (or dragging) from the ionospheric plasma is required, over a period of time, long enough for the neutrals to reach an equilibrium with regard to ion drag. Furthermore, mesoscale variations in the plasma convection morphology, solar pressure gradients, and other forces indicate that the thermosphere-ionosphere coupling mechanism will also vary in strength across small spatial scales. Using data from the Super Dual Auroral Radar Network and a Scanning Doppler Imager, a geomagnetically active event was identified, which showed plasma flows clearly imparting momentum to the neutrals. A cross-correlation analysis determined that the average time for the neutral winds to accelerate fully into the direction of ion drag was 75 min, but crucially, this time varied by up to 30 min (between 67 and 97 min) within a 1,000-km field of view at an altitude of around 250 km. It is clear from this that the mesoscale structure of both the plasma and neutrals has a significant effect on ion-neutral coupling strength and thus energy transfer in the thermosphere.
机译：以往的经验显示,在高纬度地区热电离层,突然改变等离子体速度(比如由于变化行星际磁场)立即传播到中性的气体通过离子拖带力。粒子(O,成分和甲烷)构成的thermospheric高度的质量范围,因此从先前持有剩余惯性地磁迫使水平。强迫(或拖动)一致电离层等离子体是必需的,在一段时间内时间,足够长的时间达成的中性色平衡离子拖动。中尺度等离子体对流的变化形态学、太阳能压力梯度等表明thermosphere-ionosphere力量耦合机制也将不同的力量在小空间尺度上。超级双极光雷达网络和扫描多普勒成像,眼睛活动事件显然被显示,等离子体流传授动量中性色。互相关分析确定平均时间为中性风加速完全进入离子拖动的方向是75分钟,但至关重要的是,这一次不同了30分钟(在67和97分钟)内1000公里的海拔约250公里。从这个的中尺度结构清晰等离子体和中性色明显影响ion-neutral耦合强度,因此热大气层的能量转移。

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