DE 1 Plasma Wave Instrument (PWI) Low Frequency Correlator Electric and Magnetic Field Spectral Density

Two Dynamics Explorer (DE) spacecraft were launched August 3, 1981, and placed into coplanar polar orbits with DE-1 in a highly elliptical orbit and DE-2 in a lower more circular orbit. The primary objective of the DE program was to investigate magnetosphere-ionosphere-atmosphere coupling processes. The DE mission provided a wealth of new information on a wide variety of magnetospheric plasma wave phenomena including auroral kilometric radiation, auroral hiss, Z mode radiation, narrow-band electromagnetic emissions associated with equatorial upper hybrid waves, whistler mode emissions, wave-particle interactions stimulated by ground VLF transmitters, equatorial ion cyclotron emissions, ion Bernstein mode emissions, and electric field turbulence along the auroral field lines. These files contain calibrated, full resolution, data from the DE-1 Plasma Wave Instrument (PWI). This instrument was designed and built by the plasma wave group at The University of Iowa, Department of Physics and Astronomy, in collaboration with investigators at Stanford University's STAR Laboratory. It measured plasma wave phenomena and quasi-static electric fields using paired combinations of five PWI sensors: a 200m tip-to-tip long wire electric antenna deployed in the spacecraft spin plane, a 9m tip-to-tip tubular electric antenna deployed along the spacecraft spin axis, a short 0.6m electric antenna, mounted on the boom and oriented parallel to the long wire antenna, a magnetic loop antenna mounted on the boom and oriented to measure the component of the magnetic field parallel to the long wire antenna, and a magnetic search coil antenna, also mounted on a boom and oriented to measure the magnetic field parallel to the spacecraft spin axis. The PWI main electronics unit consisted of a Step Frequency Correlator (SFC), a Low Frequency Correlator (LFC), a Wideband Analog Receiver (WBR) and a Linear Wave Receiver (LWR). Only the LFC data are included in these files. The SFC data were provided in a companion fileset. A dataset containing available high rate WBR LWR data may be provided in future archive products. The LFC consisted of two receivers (LFR-A and LFR-B) with 8 analog channels each. The analog channels were centered at 1.78, 3.12, 5.62, 10.0, 17.8, 31.2, 56.2 and 100 Hz. Each channel's band-edge was at +/-15% of the center value. Each LFR in the LFC could be connected to either the Ex, Es, Ez, or H antenna during an 8 second major frame. In addition, the Low Frequency Correlator provided in-phase and quadrature-phase correlations of signals from any selected antenna pair. Phase data are not provided in this file set.

两颗动力学探索者（Dynamics Explorer，DE）卫星于1981年8月3日发射，被部署在共面极轨轨道上：DE-1运行于大椭圆轨道，DE-2则处于更低的近圆轨道。DE计划的核心目标是研究磁层-电离层-大气耦合过程。该任务获取了海量关于各类磁层等离子体波现象的全新观测数据，涵盖极光千米辐射（auroral kilometric radiation）、极光嘶声（auroral hiss）、Z模辐射（Z mode radiation）、与赤道上杂化波相关的窄带电磁辐射、哨声模辐射（whistler mode emissions）、地面甚低频（Very Low Frequency，VLF）发射机激发的波粒相互作用（wave-particle interactions）、赤道离子回旋辐射（equatorial ion cyclotron emissions）、离子伯恩斯坦模辐射（ion Bernstein mode emissions），以及极光场线沿线的电场湍流（electric field turbulence）。
本次数据集包含DE-1等离子体波仪器（Plasma Wave Instrument，PWI）的校准全分辨率数据。该仪器由爱荷华大学物理与天文学系等离子体波研究团队设计制造，并与斯坦福大学STAR实验室的科研人员合作完成。其通过五组PWI传感器的配对组合开展测量：包括部署于航天器自旋平面内的200米尖端间距长导线电天线、沿航天器自旋轴部署的9米尖端间距管状电天线、安装在吊杆上且与长导线天线平行的0.6米短电天线、安装于吊杆以测量与长导线天线平行的磁场分量的磁环天线，以及同样安装在吊杆上以测量与航天器自旋轴平行的磁场分量的磁搜索线圈天线，可实现等离子体波现象与准静态电场的观测。
PWI主电子单元包含步进频率相关器（Step Frequency Correlator，SFC）、低频相关器（Low Frequency Correlator，LFC）、宽带模拟接收机（Wideband Analog Receiver，WBR）与线性波接收机（Linear Wave Receiver，LWR）。本次文件仅包含LFC数据，SFC数据已在配套文件集中发布。未来的归档产品可能会提供包含高速WBR与LWR数据的数据集。LFC包含两台接收机（LFR-A与LFR-B），每台配备8个模拟通道，各通道中心频率分别为1.78、3.12、5.62、10.0、17.8、31.2、56.2与100 Hz，每个通道的带宽边界为中心频率的±15%。在8秒的主帧周期内，每台LFR可连接至Ex、Es、Ez或H天线中的任意一路。此外，低频相关器还可对任意选定天线对的信号提供同相与正交相关结果，但本文件集未包含相位数据。