Laboratory Measurements of Fast Hydrogen (H) and Oxygen (O) Atom Collisions Relevant to the Upper Atmosphere

能量范围在1-100 eV及以上的快速氢、氮和氧原子是通过光解、辐射复合、解离复合、解离附着、电荷交换和超弹性(猝灭)碰撞等现象在地球上层大气中产生的。这些现象中的许多都是由闪电放电引起的，闪电放电导致了精灵、红色精灵和蓝色喷气式飞机的排放。快原子与N_2、O_2、NO、H_2O、CO_2等物质碰撞，通过化学反应或直接激发靶，在高层大气和热大气中产生氢气夜间和极点极光、热氧日冕和地冕等辐射。利用喷气推进实验室的一个独特的实验设备，在之前的NSF支持下建造，将在实验室能量范围2-100 eV内产生快速基态氢原子和氧原子。快原子将被用来研究两类与重要物种氮气、氧气和一氧化氮的大气反应。这些类别是：(A)红外(振动)激发和发射，使用耦合到HgCdTe红外探测器的积分球测量截面；和(B)电子捕获和剥离，使用潘宁离子陷阱测量截面和质量/电荷比。

Fast hydrogen, nitrogen, and oxygen atoms in the energy range 1-100 eV and higher are produced in the earth's upper atmosphere through phenomena such as photodissociation, radiative recombination, dissociative recombination, dissociative attachment, charge exchange, and superelastic (quenching) collisions. Many of these phenomena are induced by lightning discharges, which are responsible for emissions known as elves, red sprites, and blue jets. The fast atoms collide with species such as N2, O2, NO, H2O, CO2, etc. to produce, either through chemical reaction or direct excitation of the target, emissions in the upper atmosphere and thermosphere such as the hydrogen nighttime and polar-cusp aurora, and the hot oxygen corona and geocorona. Using a unique experimental facility at JPL, constructed with prior NSF support, fast ground-state hydrogen and oxygen atoms will be generated in the laboratory energy range 2-100 eV. The fast atoms will be used to study two classes of atmospheric reactions with the important species N2, O2, and NO. These classes are (a) infrared (vibrational) excitation and emission, where cross sections are measured using an integrating sphere coupled to a HgCdTe infrared detector; and (b) electron-capture and stripping, where cross-section and mass/charge ratio measurements are made using a Penning ion trap.