关键词：
Quantum-efficiency;LPIN PD-GTE;Physical models;Silicon on insulator
摘要：
Due to depleted region but not inversion region formed by the gate voltage (VGK) in thin film and ITO film with transmittancea above 80% at λ ≥ 400nm adopted as transparent electrode, high quantum efficiency (QE) could be achieved in SOI film lateral PIN photodiode gated by transparent electrode (LPIN PD-GTE). Physical models for and analysis for quantum efficiency in LPIN PD-GTE were both presented and validated by ATLAS. Quantum efficiency versus the intrinsic length was also discussed. Results indicated that the QE decreased along with the increasing channel length at VGK=0V. However, the contribution of VGK to QE was larger for longer channel in LPIN PD-GTE. The increasing amplitude were respectively, almost 8% and more than 50% for Li=10μm and Li=50μm from VGK=0V to VGK=1.0V. The increment of quantum efficiency in LPIN PD-GTE with VGK=0.6V is almost 50% to that in lateral PIN photodiode (LPIN PD) with Li=50μm and the same other parameters.
关键词：
ray tracing;electromagnetic ion cyclotron waves;bi-ion frequency
摘要：
Ray tracing study of electromagnetic ion cyclotron (EMIC) waves is conducted based on a realistic plasma density model. The simulation result shows that EMIC waves propagate away from the equatorial source region to higher latitudes basically along geomagnetic field lines, and are reflected at the region where their frequency matches the local bi-ion frequency. H+ band suffers H+-He+ bi-ion frequency reflection at lower latitudes, whereas He+ band suffers He+-O+ bi-ion frequency reflection at higher latitudes. Moreover, the concentration of heavy ions slightly affects the bi-ion frequencies and then slightly determines the reflection location of ray paths of EMIC waves. The current results present the first detailed study on the propagation characteristics of EMIC waves associated with bi-ion frequencies.
关键词：
FREQUENCY CHARACTERISTICS;LPIN PD-GTE;PHYSICAL MODEL;SOI
摘要：
Frequency characteristics in lateral PIN photodiode gated by transparent electrode (LPIN PD-GTE) were studied by physical models and numerical simulation. In LPIN PD-GTE, due to vertically depletion in thin film by gate voltage, wider lateral depleted region and shorter transmit time were obtained than that in lateral PIN photodiode (LPIN PD) with the same parameters. Physical models and analysis for -3dB frequency, f<inf>T</inf> were presented and validated by ATLAS. Results indicate that the f<inf>T</inf> of LPIN PD-GTE at V<inf>GK</inf> = 0.6 V (f<inf>T</inf> = 30 MHz) is higher than that of LPIN PD (fT = 3 MHz) under the same parameters. Influences of key parameters, such as thickness of front oxide and channel length were discussed furthermore to predict and optimize their speed performances for the target applications.
摘要：
In this study, we analyze Cluster observations of whistler-mode chorus and hiss waves during the event of August 19-21, 2006. Chorus is present outside the plasmasphere and hiss occurs inside the plasmasphere. Using a recently constructed plasma boundary layer model, we perform a ray-tracing study on the propagation of chorus. Numerical results show that chorus can penetrate into the plasmasphere through the plasma boundary layer, evolving into hiss. The current data analysis and modeling provide a further observational support for the previous findings that chorus is the origin of plasmaspheric hiss.
摘要：
Understanding excitation of electromagnetic ion cyclotron (EMIC) waves remains a considerable scientific challenge in the magnetospheric physics. Here we adopt correlated data from the Thermal Emission Imaging System (THEMIS) spacecraft under low (K-p = 1(+)) and medium (K-p = 4) geomagnetic activities to investigate the favorable conditions for the excitation of EMIC waves. We utilize a sum of bi-Maxwellian components and kappa components to fit the observed ion (6-25 keV) distributions collected by the electrostatic analyzer (ESA) onboard the THEMIS spacecraft. We show that the kappa distribution models better and more smoothly with the observations. Then we evaluate the local growth rate and path-integrated gain of EMIC waves by bi-Maxwellian and kappa distributions, respectively. We demonstrate that the path-integrated wave gain simulated from the kappa distribution is consistent with observations, with intensities 24 dB in H+ band and 33 dB in He+ band. However, bi-Maxwellian distribution tends to overestimate the wave growth rate and path-integrated gain, with intensities 49 dB in H+ band and 48 dB in He+ band. Moreover, compared to the He+ band, a higher proton anisotropy is needed to excite the H+ band waves. The current study presents a further observational support for the understanding of EMIC wave instability under different geomagnetic conditions and suggests that the kappa-type distributions representative of the power law spectra are probably ubiquitous in space plasmas. Citation: Zhou, Q., F. Xiao, J. Shi, C. Yang, Y. He, and L. Tang (2013), Excitation of electromagnetic ion cyclotron waves under different geomagnetic activities: THEMIS observation and modeling, J. Geophys. Res. Space Physics, 118, 340-349, doi:10.1029/2012JA018325.
摘要：
In this paper, we develop a physical model to evaluate the detector coil inductances for ring-core fluxgate sensors. Using realistic magnetization parameters, we study the inductance variation with different excitation currents. We perform the corresponding experiments to measure the detector coil inductances, and find that the average deviation between the calculated and the measured results is less than 5.7%. We also investigate the influence of the distance between coil sections and the winding area on the detector coil inductances. The results reveal that the inductance model can be used to determine the geometry and the size of the sensor.
