Subjects: Geosciences >> Space Physics submitted time 2017-01-22
Abstract: Long term high energy electron irradiation may affect performance of the Si-PIN semiconductor detector (SSD).In order to assess the life of the detector in space radiation environment, electron irradiation source was used to simulate space electron environment, and the irradiation experiments were carried out on the semiconductor detector. Experiment results show that under the radiation dose of 7.64×1014, the SSD’s energy response capability had not changed, and the counting efficiency slightly decreased. As the radiation dose increased, the leakage current of the SSD increased, but the noise was relatively stable, and the performance of the detector did not affect the work index of the load.
Peer Review Status:Awaiting Review
Subjects: Geosciences >> Space Physics submitted time 2017-01-22
Abstract: As the thin air in the upper atmosphere(~250 km), passive optical measurement is considered as the most efficient method for wind retrieval of the upper atmosphere. Because of high energy utilization and high spectral resolution, Fabry-Perot Interferometer (FPI)is one of the most widely used instruments for wind measurements. To date, FPI has been used for wind measurements from both space and ground for decades. Many countries observed OI 630.0 nm nightglow emission to retrieve wind velocities by use of kinds of FPIs. In this paper, a tiny ground-based Fabry-Perot Interferometer (FPI) is designed using a band-pass filter behind etalon and Galilean telescope system for wind observation of the upper atmosphere. The instrument is mainly composed of five parts including front optics sky-scanner, the etalon, Galilean telescope and filter, detector, and laser calibration system. The size of the instrument is 1.34�.58�.35 m3, which demonstrates that the FPI is convenient to be transported from one place to another. Based on the instrument, several days of experiments were carried out at Langfang (39.40癗, 116.65癊) site and Kelan (38.71�N, 111.58�E) site for a detailed validation. The averaged wind deviation at Kelan sites between our FPI and American A-NCAR FPI is 11.8 m/s, which suggests good agreement between them.
Peer Review Status:Awaiting Review
Subjects: Geosciences >> Space Physics submitted time 2017-01-22
Abstract: The managing project was researched on this paper for payload self-explore of DAMPE-Satellite, analyzing about payload’s work-modes of the explorer. The designing method and the software realization result was given out for the payload’s self-explore base on event-driven, which was conjoint by programming-experts on the ground and perform-units on the satellite. Meanwhile, the reliability & security measures was studied. The test results were provided: the function of anytime and anywhere for skillful exploring of the satellite was implemented. And it reduces the workload of the remote control.
Peer Review Status:Awaiting Review
Subjects: Geosciences >> Space Physics submitted time 2017-01-22
Abstract: Solar activity and Earth's space environment can effect the operation and safety of spacecraft, and they are also the main error source of navigation, positioning, and communication based on radio waves applications system. In this field, the L-band solar radio burst is regarded as a potential threat to Global Navigation Satellite System(GNSS) stability and performance. When the solar radio burst exceeds a threshold value, the radio noise from solar emission will increase dramatically, which can give rise to GNSS receiver tracking loss and positioning failure located in the sunlit hemisphere of the Earth. In this paper, by using the solar radio flux data, L-band scintillation data, and GPS receiver observation network data located in different regions, effect of the 13 December 2006 solar radio burst on GPS observations are investigated in detail. Results show that the disruption caused by this radio burst event is obvious, and the amplitude scintillation events occur and GPS signal losses of lock are detected. Furthermore, the GPS satellite signal locked at several GPS station is interrupted and the observed GPS satellite number is less than 4 during this solar radio burst. The event resulted in GPS service failure for about six minutes. By comparison, those stations located nearby sub-solar point are more serious than that of far away from it.
Peer Review Status:Awaiting Review
Subjects: Geosciences >> Space Physics submitted time 2017-01-22
Abstract: A technique of using a semiconductor diode volt-ampere characteristic to test Langmuir probe performance is presented. The Langmuir probe is an important technique for in-suit detecting the space plasma, and its performance test is the key to ensure that its technical indicators can meet the mission requirements. The technique of using a semiconductor diode volt-ampere characteristic demands less of external factors, so it can be carried out in a laboratory environment. The test results can be used as preliminary performance verification before calibration test of ground plasma environment, and it is proved that the method is effective and feasible in a lab environment test.
Peer Review Status:Awaiting Review
Subjects: Geosciences >> Space Physics submitted time 2017-01-22
Abstract: With the increase of explored data, in order to improve data display result and efficiency, reasonable data arrangement is needed. In this paper, based on the solar wind data characteristics, the SDOG-R grid which is radial independent division in the adaptive SDOG grid is mainly elaborated. In order to make data applicable to the model, a centroid interpolation algorithm based on three-dimensional spherical coordinate system is proposed to re-sample the original data. The division model not only applies to both regular and irregular sampling data, but also maintains the characteristics of original data to the best and encodes grids with improved CDZ curve. The model not only resolves the problem that grids at the two poles and the center of the sphere are too dense, but also resolves the problem that radial resolution is greater than spherical resolution. Keywords: solar wind; space subdivision; SDOG-R;encoding
Peer Review Status:Awaiting Review
Subjects: Geosciences >> Space Physics submitted time 2017-01-22
Abstract: With the massive increase of space exploration data, in order to improve the visibility effect and data access efficiency, effective organization and management is needed. In this paper, based on the existing 2D subdivision models, combined with the solar wind data characteristics, for the ecliptic plane and meridian plane which are over the sun centroid, a new model, applicable to solar wind data, is put forward, PDQG, namely plane degradation quad-tree grid. Based on improved degradation Z curve Grids, encoding scheme of grids is given. The model not only resolves the problem that grids near to heliocentric are too dense, but also meets the requirement that resolution in radius is not equal to that in longitude and latitude, provides hierarchical multi-resolution data. It can support the organization and management of massive space data effectively.
Peer Review Status:Awaiting Review
Subjects: Geosciences >> Space Physics submitted time 2017-01-22
Abstract: The unique combination of global coverage, high precision, high vertical resolution, long-term stability and all-weather viewing of radio occultation will enhance the data sets of numerical weather prediction and improve the precision of Numeric Weather Prediction (NWP). And data assimilation requires preprocessing of the raw radio signals into the bending angles and refractivity. Then the atmospheric parameters such as temperature, pressure and humidity can be retrieved through data variational assimilation. The procedures for processing of radio occultation data, especially several important steps are introduced. And comparative analysis between these results and those from CDAAC shows that below the altitude of 30 km, the relative errors of refractivity, pressure and humidity are within 2% and the deviation of temperature is below 2K. The results are also compared with the data from ERA-interim model of ECMWF and similar conclusion is obtained.
Peer Review Status:Awaiting Review
Subjects: Geosciences >> Space Physics submitted time 2016-05-13
Abstract: A new bi-phase modulation (BPM) pulse UWB transmitter manufactured by discrete components is designed. The transmitter consists of mono-polar sub-nanosecond pulse generator, bipolar pulse generator,and high speed microwave switch. The transmitter transmit positive and negative pulses when controlled by clock signal as well as data ' 1' and data ' 0',respectively. Experimental results show that the generated pulse width is below 400 ps,the bandwidth is more than 1. 5 GHz,and the data rate is up to 50 Mbps. It can be used in the pulse UWB (ultrawideband) communication systems.
Peer Review Status:Awaiting Review
Subjects: Geosciences >> Space Physics submitted time 2016-05-13
Abstract: In this paper, the correlation between various parameters of solar cycles 0-23 is investigated. The parameters include maximum, rising time and descending time. Three derived regression equations are given between maximum and rising time. Two derived regression equations are given between descending time and total of descending time and next rising time. Additionally, according to the cycle periodicity of secular trend and the regularity of maximum between even cycles and following odd cycles, the prediction of cycle 25 is obtained. It is expected that solar cycle 25 will begin in June 2020 and will be relatively stronger than cycle 24. The sunspot number maximum of cycle 25 is predicted to occur in April 2024 with a sunspot number of 119.25.5, which will be nearly the same strength of cycle 17 and 23.
Peer Review Status:Awaiting Review
Subjects: Geosciences >> Space Physics submitted time 2016-05-13
Abstract:利用全天时钠层荧光激光雷达和GPS电离层探测仪, 在2009年7月22日武汉日全食期间, 开展钠层与电离层的联合观测试验. 观测结果表明, 钠层密度半高全宽在日全食过程中稍有变窄, 而日全食过后增宽, 钠层峰值高度在日全食过程中稍有降低, 日全食过后高度略增, 钠层变化特性表现出快速的日出日落过程. 电离层电子总含量和天空背景光噪声也随日全食期间太阳辐照的变化而呈现出明显下降和上升的波动特征. 所不同的是, 钠层原子的这种半宽度起伏变化要比电离层的变化迟缓得多, 这可能是由于钠层受到日全食辐照扰动后, 会产生一系列复杂的光化学反应及动力输运过程, 再复合成钠原子被激光雷达探测到, 有一个滞后过程, 这也正好与理论模拟的结果相符.
Peer Review Status:Awaiting Review
Subjects: Geosciences >> Space Physics submitted time 2016-05-13
Abstract:TC-2卫星上的中性原子成像仪(NUADU)在2005年5月15日磁暴期间(并伴随有系列亚暴事件)记录了反映环电流离子连续变化的能量中性原子(ENA)图像探测数据. 比较由中性原子图像反演的4 min时间分辨的环电流离子空间分布与地球同步轨道LANL系列卫星(环绕赤道面~6.6 R_E)上同步轨道粒子分析仪(LANL-SOPA)原位离子通量探测数据, 以及相同高度的同步系列卫星GOES的磁场数据, 发现环电流区离子通量增长发生在磁力线尾向拉伸的亚暴增长相阶段, 而不是发生在磁场偶极化之后. 这一发现挑战了以往的环电流离子注入是磁场偶极化时由磁尾直接注入的概念, 但仍需更多的观测实例进一步认证.
Peer Review Status:Awaiting Review