Subjects: Physics >> Condensed Matter: Structural, Mechanical and Thermal Properties submitted time 2017-01-23
Abstract：In this note, we point out that a case of mechano-caloric effect of superfluid $^4$He actually establishes a temporary entropy-decreasing process, which was unnoticed in the past. We show that this process can be used to convert thermal energy from the environment to useful energy in principle, and therefore, the second law of thermodynamics is not an universal law.
Peer Review Status:
Awaiting Review
Subjects: Geosciences >> Space Physics submitted time 2017-01-22
Abstract： Based on the 2755 days’ (2001-05-15~2008-12-31) density data derived from CHAMP accelerometer, the model errors of JB2008 and MSISE-00 are analyzed. It is found that the two modes both overestimate the atmospheric density, but the JB2008 is better than the MSISE-00, their average bias is 2.2% and 17.6% respectively. To brief classification of space environment, the model characteristics of latitudes and local time are analyzed in each class space environment. It is found that MSISE-00 model has better local time characteristic and JB2008 has good latitude characteristics. This study has certain significance to master model error characteristics and to improve atmospheric density model.
Peer Review Status:Awaiting Review
Subjects: Geosciences >> Space Physics submitted time 2017-01-22
Abstract： Wind and temperature data detected by the first meteorological rocket of the Meridian Space Weather Monitoring Project was used tostudy quasi-monochromatic inertia gravity waves over Hainan rocket launch site(19.5°N,109°E).The GW extracted from the stratosphere (troposphere)revealed by rocketsonde is upward(downward) GW,both propagate against the background wind.The intrinsic period, vertical wavelength ，horizontal wavelength ，vertical group velocity ,and horizontal group velocity of Stratospheric(Tropospheric)GWare 20.1 h(22.4 h),9.5 km(4 km), 2900 km(753 km) ,0.0887（0.0298）m/s,and12.7（3.65）m/srespectively. There is a significant difference between and because of the background wind. The ratio and is 305:1(188:1) and 143:1(122:1) for the stratospheric(tropospheric) GW, the former is about 1.62(1.17) times of the latter.
Peer Review Status:Awaiting Review
Subjects: Geosciences >> Space Physics submitted time 2017-01-22
Abstract： In order to ensure quantum science experiments can be developed smoothly, a high data rate two-way link for Space-Ground microwave communication must be established. Via following the study on Consultative Committee for Space Data Systems (CCSDS) and taking into account the scientific requirements of microwave communication link for quantum science experiment satellite, the physical layer hardware architecture and modulation/demodulation algorithm of microwave communication link for the satellite are presented.The uplink modulation type of the microwave communication link is SRRC-OQPSK, which accord with CCSDS spectrum standard. The specification of uplink data rate is 1.024Mbps,. The downlink modulation type of the microwave communication link is SRRC-OQPSK/GMSK, and the data rate is 4Mbps. By compatible tests with several ground stations, we find that the sensitivity of carrier acquisition is superior to -100dBm, and AGC ability is greater than 43dB. Moreover, the bit error rate of actual transmission is superior to 1�0-9 as the received signal level is equal to -96 dBm. The measured results indicate that the physical layer design scheme of microwave communication link meets the requirements of space quantum science experiments.
Peer Review Status:Awaiting Review
Subjects: Geosciences >> Space Physics submitted time 2017-01-22
Abstract： The Neutral Atom Image System with High energetic particles (NAIS-H) developed for a Chinese mission of Magnetosphere Ionosphere and Thermosphere (MIT) capable to obtain the global map of the plasma distribution with a high temporal-spatial resolution in support this mission. The calibration of detector was an important technical task in the development, which is the fundamental basis of data analysis and inversions.
Peer Review Status:Awaiting Review
Subjects: Geosciences >> Space Physics submitted time 2017-01-22
Abstract： Multi-point synchronous magnetic field measurements can give more accurate space current density compared with the traditional single-point measurement, since multi-point measurement can eliminate the temporal change in the magnetic field. Based on the current density inversion method for multi-point magnetic field measurements, through simulation, several factors affecting space current density inversion are analyzed, such as the number of satellites, satellite formation configuration, satellite positioning precision, satellite attitude determination error, magnetic field measurement accuracy, external magnetic field intensity, external current density and so on. It is shown that 5-point measurements are better than 4-point measurements, and error in attitude determination and external magnetic field intensity are the main factors causing the error in current density inverted, while satellite formation configuration is also an important factor. According to the simulation, the maximum error in current density is less than 24% near the equator when the attitude determination error is 0.001癮nd the scale of the satellite formation is about 100km.
Peer Review Status:Awaiting Review
Subjects: Geosciences >> Space Physics submitted time 2017-01-22
Abstract： Combining the GRO (Global Navigation Satellite System Radio Occultation GRO) and LRO (Low Earth Orbit Radio Occultation) techniques to probe the Earth's atmosphere is a main development direction of RO. In this study, the mathematical criteria of a RO event have been described. Then the effects of the main orbit parameters of LEO satellite on the RO events amount and their global distribution have discussed by a simulation study. The results showed that the lower the LEO satellite orbit is, the more GRO events are; when the inclination is between 30癮nd 75� there are more GRO events and their Earth coverage is higher. The LRO events distribute on the Earth evenly when the LEO-LEO RO satellite set in the polar orbits. This study can provide a scientific reference for GRO and LRO satellite constellation design.
Peer Review Status:Awaiting Review
Subjects: Geosciences >> Space Physics submitted time 2017-01-22
Abstract： In order to analyze the radiative transfer characteristics of planetary atmosphere in the microwave and sub millimeter wave bands, the absorption coefficient of the gases included in planetary atmosphere are calculated by using line-by-line integration method. Based on the parameters of gas molecules in HITRAN database, such as the transition frequency, line strength and so on, the absorption feature of every gas molecule in the 1-3THz frequency range is simulated and compared with the existing atmospheric radiative transfer model of the Earth. As an example, the radiation transport characteristics of Earth’s and Mars’ atmosphere are analyzed and the brightness temperature of Earth’s atmosphere radiative transfer is simulated by using radiative transfer equation. The work in this article provides the model and theoretical basis for the selection of detection frequency band of planetary atmospheric composition and for the retrieval of atmosphere profiles.
Peer Review Status:Awaiting Review
Subjects: Geosciences >> Space Physics submitted time 2017-01-22
Abstract： Based on an extremely disturbed field-aligned electrons event observed with Cluster in the northern cusp region on September 30, 2001, the energy features of the field-aligned electrons in the event was analyzed and the role of the field-aligned electrons on the solar wind energy transfer into the magnetosphere and on the magnetosphere-ionosphere coupling. The results show that the velocities and densities of the electrons have strong disturbances during the event, and the velocity is main factor to enhance the electron flux. The energy spectrum in the 5~200eV and 500~1500eV show that the up-flowing electron flux is higher than down-flowing, which means the up-flowing electrons are from the ionosphere and play a active role in this event. The features of the energy show that the ionospheric electrons have been accelerated during the up-flow. However, the physical mechanism still needs to be further studied.
Peer Review Status:Awaiting Review
Subjects: Geosciences >> Space Physics submitted time 2017-01-22
Abstract： A minor sudden stratospheric warming(SSW) event occurred in the early and middle January of 2014. The amplitude of increasing temperature was about 25K , the zonal eastward wind became weaker and shifted its direction until the early February. The planetary waves (PWs) are believed to have significant role in SSW events. So using the wind data detected by 5 meteor radars at low and middle latitude of northern hemisphere near 120 , we studied the PWs during this minor SSW event. Results show that the enhanced quasi 16-day PWs can be found at mesosphere and lower thermosphere (MLT) region. The enhancement of quasi 16-day waves were prior to the warming, and the quasi 16-day PWs had mostly the strongest amplitude when the polar temperature reach its peak. This demonstrates the coupling between low and middle latitude MLT region and SSW. Furthermore, we used the reanalysis data from the European Centre for Medium-range Weather Forecasts (ECMWF) to investigate the wave coupling between stratosphere and mesosphere. The band pass filter of the stratospheric temperature shows that quasi 16-day PWs propagated period lower latitude to the pole, meanwhile the zero-wind line moved from low latitude to high latitude, indicating a dynamical connection between the 16-day PWs and SSW.
Peer Review Status:Awaiting Review
Subjects: Geosciences >> Space Physics submitted time 2017-01-22
Abstract： SET effect has become an important factor to threaten the reliability of spacecraft. In this paper, the effects of different irradiation positions, different laser energy and different laser focusing depth on SET pulse are measured. According to the worst case, the Hspice circuit level simulation is carried out to study the effect of different parameters on the SET pulse. In the end, the effect of the Suppressor is verified.
Peer Review Status:Awaiting Review
Subjects: Geosciences >> Space Physics submitted time 2017-01-22
Abstract： By studying Rayleigh lidar data，The seasonal variations of atmospheric temperature of 35-70km in Beijing area are analyzed.The atmospheric temperature between 30-70km height range at Beijing region has obvious annual cycle variation. The highest temperature in the stratosphere appeared in June and July, which is about 270K. The lowest temperature in the middle layer 70km is also in June, July, about 200K. Take the data of October 14, 2014 as an example， Gravity wave dissipation under 50km is found，while， the gravity waves propagate upward almost without dissipation above 50km.By comparing the average potential energy density between 35-50km height range, the seasonal variation of the gravity waves activities intensity in the Beijing area was studied. The gravity waves activities over Beijing have an obvious cycle of one year.The average potential energy density in winter is , while in summer, the average potential energy density is , the gravity waves activities intensity in winter is about two times of that in summer. In addition, the profile of seasonal averaged gravity waves potential energy density are given in spring,summer,autumn and winter. The dissipation of gravity waves in different seasons and different heights is analyzed in Beijing area.
Peer Review Status:Awaiting Review
Subjects: Geosciences >> Space Physics submitted time 2017-01-22
Abstract： A general design of solar neutral atom code mask imager (SONACOMI) is proposed. The instrument is designed to measure the solar energetic atom emitted from the solar flare or CME, measuring the differential energy spectrum of ENAs between 0.5MeV/u and 6MeV/u and FOV of ENAs covering . This instrument combines innovative sensor geometry, an m series coding mask modulation aperture, and a combination of high voltage deflecting plate of active and passive shielding charging particles to obtain ENAs in space flight.
Peer Review Status:Awaiting Review
Subjects: Geosciences >> Space Physics submitted time 2017-01-22
Abstract： This study use the wind data from the observation of China Langfang (39°N，117°E) meteor radar during the 1 April 2012 to 31 March 2013 to investigate the features of the mesospheric and lower thermospheric mean winds within 80-100 km altitude regions. The results show that the mean zonal winds and mean meridional winds both have obviously seasonal variations. During the winter, eastward winds prevail in the MLT ranges, which is strong in mesosphere and decrease versus increasing altitude. In the summer, westward winds dominate in mesosphere, and decrease along with increasing altitude, then turn to the strong eastward in lower thermosphere. The wind evolution in the spring and autumn are the transition characters between the summer and winter. The mean meridional winds are southward in summer and northward with sometimes reversal in winter, in general. The above main seasonal variations of mean winds are captured largely by the simulation of WACCM4 model and HWM93 model. WACCM overestimates the winds, but HWM93 underestimates the winds.
Peer Review Status:Awaiting Review
Subjects: Geosciences >> Space Physics submitted time 2017-01-22
Abstract： Parameterized ionosphere model TIEGCM is used as background model. Basing on the COSMIC observations, global ionospheric electron density assimilation model is established using ensemble Kalman filter. Result shows, this model can effectively assimilate observations into background model and acquire three dimensional ionospheric electron density. Compared to background, the error between analysis and observations decreases significantly. The root mean square error(RMSE) of NmF2 decreases about 60% for observations assimilated, and 20% for observations not assimilated. The RMSE of hmF2 doesn’t get improvement except for mean error. The results of simultaneous assimilation (SA) and batches assimilation (BA) are compared for this case. The time that the two methods spend in assimilation is about 6 to 7 minutes, which does not differ very much. SA needs nearly 8 GB storage while BA less than 2GB. The statistic of electron density error shows that they nearly acquire the same mean error, but the SA gets relative better improvement in RMSE above 250km.
Peer Review Status:Awaiting Review
Subjects: Geosciences >> Space Physics submitted time 2017-01-22
Abstract： The problem of minimum-fuel aeroassisted orbital transfer of a high lift-to-drag ratio vehicle from Low Earth Orbit (LEO) or Geostationary Earth Orbit (GEO) to low-Earth orbit with an inclination change is considered. Assuming impulsive thrust, the trajectory design is described in detail and the aeroassisted orbital transfer is posed as a nonlinear optimal control problem. Through comparison of the double-impusive orbit transfer and aeroassisted orbit Transfer in noncoplanar orbit, we concluded the influence of altitude difference from two noncoplanar orbits and the perigee choice of the middle transtion orbit. The main problem that aeroassisted orbital transfer may face is hypersonic flight in the upper atmosphere. In the end the technology used in X-37B flight was concluded.
Peer Review Status:Awaiting Review
Subjects: Geosciences >> Space Physics submitted time 2017-01-22
Abstract： Solar proton event forecast is very important to guarantee the security of spacecrafts and astronauts. According to the short to medium term space mission, the greater than 10 MeV, 30 MeV and 60 MeV solar proton event fluences are statistically analyzed. It is found that the probability distributions of solar proton event fluences basically satisfy the log-normal distributions, and their expectations and averages are logarithmic functions of the time periods. Based on these, a short to medium term forecast model of solar proton event fluences is built, which can forecast the greater than 10 MeV, 30 MeV and 60 MeV solar proton event fluences with some given confidence levels for 1 to 365 days. So, this model is very helpful to safely carry out the space mission with less than 1 year mission period.
Peer Review Status:Awaiting Review
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： Slitless imaging spectrometer allows imaging spectroscopy with high spatial and temporal resolution. Slitless imaging technique is a revolutionary technique for solar research in the extreme ultraviolet band. Combined with the international and domestic development status of solar extreme ultraviolet imaging spectrometer, we propose a new idea of optical design. We have proved the effectiveness of this design by reconstructing the simulated data. The reconstruction of new design shows better measurement accuracy in doppler velocity. It will provide more accurate data and improve the research level of space weather.
Peer Review Status:Awaiting Review
Subjects: Geosciences >> Space Physics submitted time 2017-01-22
Abstract： In this paper, the observational investigation shows that the blurred echoes traces, as the expression of occurrence of spread-F, are occurred on the day time at mid-latitude regions based on the analyses of the HF Doppler frequency shift data; Simultaneously, the other ionospheric disturbances accompanied with or immediately before or after or following spread-F are also recorded. The results show that there are several aspects of the characteristics of the daytime spread-F-like phenomena observed by the HF Doppler sounding as following: 1) occurrence time cover almost the whole daytime, such as: the time period of morning, from morning to noon and the time period of afternoon; 2) the morphological features are the blurred echoes traces (similar as the nighttime spread-F), the shifts of which tend to be positive, and sometimes are accompanied by traveling ionospheric disturbances (TIDs) that are not the characteristics of the one generated by typhoon; 3) duration time is much longer, the longest one lasts about five hours; 4) it appears accompanying with the other ionospheric disturbances such as TIDs, solar flare etc.. The characteristics show that the HF Doppler sounding is useful tool for detecting the daytime spread-F-like. Although the daytime spread echoes phenomenon occasionally occur and the occurrence rate is very low, the extensiveness of temporal and spatial distribution of the daytime spread-F-like implies that its effect on the space weather can not be ignored and its properties can not be replaced by the one of the usual spread-F. Therefore, the study of the daytime spread-F-like has very important significance.
Peer Review Status:Awaiting Review
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