Extreme Ultraviolet Camera Research Articles

Diagnostic and Power Feed Upgrades to the MAIZE Facility

The Michigan Accelerator for Inductive Z-pinch Experiments (MAIZE) is a single-stage, 1-MA linear transformer driver at the University of Michigan. The MAIZE facility has been the site of various experimental studies, including wire array Z-pinches for X-ray source development and cylindrical foil loads for implosion stability analysis. In order to better understand and investigate these and other experiments, a 4-frame extreme ultraviolet camera was implemented, the optical stability of a 12-frame laser shadowgraphy system was improved, B-dot probes were upgraded, and a Rogowski coil was constructed. New conical load hardware was also developed to reduce the inductance of the transmission line and thus improve the current delivered to the loads.

Imaging the Global Distribution of Plasmaspheric Oxygen

AbstractThis paper investigates the potential for 83.4 nm imaging of the plasmaspheric dense oxygen torus, using simple models for core plasma density and composition to constrain a simulated image code. We derive the requirements for plasmaspheric O+imaging, and the expected performance of an imager based on a slightly modified version of the IMAGE extreme ultraviolet camera. We find that such an imager can achieve a sensitivity of 0.69(s R pixel)−1, sufficient to capture the dense torus 83.4 nm signal with 25 min integration time. The background rejection ratios for this design are 1.5 × 10−4at 58.4 nm and 7.4 × 10−8for Lyman‐α. We discuss the effects of ion temperature and motion, and O++glow. We compute simulated O+images of the formation and global distribution of the dense torus. We also examine the possibility of direct observation of oxygen outflow from the ionosphere.

月基极紫外相机指向机构控制系统

月基极紫外相机指向机构控制系统

月基极紫外相机软件系统的设计与实现

月基极紫外相机软件系统的设计与实现

Correlations between plasmapause evolutions and auroral signatures during substorms observed by Chang’e-3 EUV Camera

The plasmapause locations determined from the Chang’e-3 (CE-3) Extreme Ultraviolet Camera (EUVC) images and the auroral boundaries determined from the Defense Meteorological Satellite Program (DMSP) Special Sensor Ultraviolet Spectrographic Imager (SSUSI) images are used to investigate the plasmaspheric evolutions during substorms. The most important finding is a nightside pointing plasmaspheric plume observed at 23:05 UT on 21 April 2014 under quiet solar wind and geomagnetic conditions, which drifted from the dusk sector. High correlations between the plasmapause evolutions and the auroral signatures exist during substorms. After substorm onset, the plasmapause erosion and the equatorward expansion of the auroral oval occur almost simultaneously in both MLT and UT, and then both the erosion and the expansion propagate westward and eastward. It is suggested that the plasmaspheric erosion and its MLT propagations are induced by the enhanced earthward plasma convection during substorm period, and the substorm dipolarization causes pitch-angle scattering of plasma sheet electrons and the resulting precipitation excites aurora emissions at the same time.

Response of plasmaspheric configuration to substorms revealed by Chang'e 3.

The Moon-based Extreme Ultraviolet Camera (EUVC) of the Chang’e 3 mission provides a global and instantaneous meridian view (side view) of the Earth’s plasmasphere. The plasmasphere is one inner component of the whole magnetosphere, and the configuration of the plasmasphere is sensitive to magnetospheric activity (storms and substorms). However, the response of the plasmaspheric configuration to substorms is only partially understood, and the EUVC observations provide a good opportunity to investigate this issue. By reconstructing the global plasmaspheric configuration based on the EUVC images observed during 20–22 April 2014, we show that in the observing period, the plasmasphere had three bulges which were located at different geomagnetic longitudes. The inferred midnight transit times of the three bulges, using the rotation rate of the Earth, coincide with the expansion phase of three substorms, which implies a causal relationship between the substorms and the formation of the three bulges on the plasmasphere. Instead of leading to plasmaspheric erosion as geomagnetic storms do, substorms initiated on the nightside of the Earth cause local inflation of the plasmasphere in the midnight region.

Analysis of observational data from Extreme Ultra-Violet Camera onboard Chang’E-3 mission

The Extreme Ultra-Violet Camera (hereafter EUVC) is a scientific payload onboard the lander of the Chang’E-3 (hereafter CE-3) mission launched on December 1st, 2013. Centering on a spectral band around 30.4 nm, EUVC provides the global images of the Earth’s plasmasphere from the meridian view, with a spatial resolution of \(0.1~R_{\oplus}\) in \(150 \times 150~\mbox{pixels}\) and a cadence of 10 minutes. Along with the data being publicly released online, some unsettled issues in the early stage have been clarified, including the geometrical preparations, the refined approach on the coefficient \(K\) for the background, and the alignment among the images. A demo of data after all the above processes is therefore presented as a guidance for users who are studying the structure and dynamics of the plasmasphere.

Determination of the Earth's plasmapause location from the CE‐3 EUVC images

AbstractThe Moon‐based Extreme Ultraviolet Camera (EUVC) aboard China's Chang'e‐3 (CE‐3) mission has successfully imaged the entire Earth's plasmasphere for the first time from the side views on lunar surface. An EUVC image on 21 April 2014 is used in this study to demonstrate the characteristics and configurations of the Moon‐based EUV imaging and to illustrate the determination algorithm of the plasmapause locations on the magnetic equator. The plasmapause locations determined from all the available EUVC images with the Minimum L Algorithm are quantitatively compared with those extracted from in situ observations (Defense Meteorological Satellite Program, Time History of Events and Macroscale Interactions during Substorms, and Radiation Belt Storm Probes). Excellent agreement between the determined plasmapauses seen by EUVC and the extracted ones from other satellites indicates the reliability of the Moon‐based EUVC images as well as the determination algorithm. This preliminary study provides an important basis for future investigation of the dynamics of the plasmasphere with the Moon‐based EUVC imaging.

嫦娥三号极紫外相机几何定位方法及其应用

嫦娥三号极紫外相机几何定位方法及其应用

Curved focal plane extreme ultraviolet detector array for a EUV camera on CHANG E lander.

A novel curved focal plane extreme ultraviolet (EUV) detector array designed for a moon-based EUV camera is demonstrated. The curved focal plane detector array operating in a pulse-counting mode consists of a curved microchannel plate (MCP) stack and an induced charge wedge-strip anode (WSA). The curved MCP is fabricated by firstly thermally slumping of the MCPs, and then followed by optical polishing and core glass etching. By using this technology, curved MCPs with a length-to-diameter (L/D) ratio of 80:1 and a radius of curvature of 150 mm have been successfully achieved. The performance of the curved MCP detector is fully characterized in terms of the background noise, pulse height distribution, gain, image linearity and spatial resolution. It is measured that a spatial resolution of 7.13 lp/mm can be achieved with a background noise of less than 0.3 counts/cm2⋅s. The characterization results indicate that the curved focal plane detector can fulfill the requirements of the moon-based EUV camera.

Geocentric position preliminary detection from the extreme ultraviolet images of Chang’E-3

An Extreme ultraviolet (EUV) Camera was installed onboard the Chinese lunar surface landing mission, the Chang’E-3 lander, as a useful method to observe the Earth plasmasphere. This EUV optical payload obtained more than 600 moon-based Earth plasmasphere images since December 14, 2013. However, due to errors of unknown size and origin in the platform attitude control of the lander and in the EUV telescope pointing control during the mission operating periods, the geocentric coordinates in these EUV images are not fixed in the same position of CCD pixel. Before adequately calibrating, these positioning offsets will introduce extra errors into the analysis of the plasmaspheric structure. With only a little insufficient telemetry information, an effective calibrating method of circle-based differential algorithm is suggested and demonstrated, for automatically and precisely detecting the geocentric position in each EUV image of Chang’E-3 mission. In each EUV image, the tested method uses the outline of a circle as the basic unit to capture the contour for the bright region based on the spectral characteristic. Then, the center of the extracted circle is adopted as the geocentric position for the image. The preliminary analysis shows that this method can effectively detect the geocentric position being always consistent with the recognition result by the basic hand labor method. It is found that the radius of the circles varies from month to month from December, 2013 to May, 2014. The monthly averages of radius show relative notable positive correlation and negative correlation with the changes of both Zenith angle of the Earth at the landing area of Chang’E-3 lander, and the Earth-moon distance, respectively. This method and results here will benefit the Chang’E-3 EUV study.

The Chang’e 3 Mission Overview

The Chang’e 3 (CE-3) mission was implemented as the first lander/rover mission of the Chinese Lunar Exploration Program (CLEP). After its successful launch at 01:30 local time on December 2, 2013, CE-3 was inserted into an eccentric polar lunar orbit on December 6, and landed to the east of a 430 m crater in northwestern Mare Imbrium (19.51°W, 44.12°N) at 21:11 on December 14, 2013. The Yutu rover separated from the lander at 04:35, December 15, and traversed for a total of 0.114 km. Acquisition of science data began during the descent of the lander and will continue for 12 months during the nominal mission. The CE-3 lander and rover each carry four science instruments. Instruments on the lander are: Landing Camera (LCAM), Terrain Camera (TCAM), Extreme Ultraviolet Camera (EUVC), and Moon-based Ultraviolet Telescope (MUVT). The four instruments on the rover are: Panoramic Camera (PCAM), VIS-NIR Imaging Spectrometer (VNIS), Active Particle induced X-ray Spectrometer (APXS), and Lunar Penetrating Radar (LPR). The science objectives of the CE-3 mission include: (1) investigation of the morphological features and geological structures of and near the landing area; (2) integrated in-situ analysis of mineral and chemical composition of and near the landing area; and (3) exploration of the terrestrial-lunar space environment and lunar-based astronomical observations. This paper describes the CE-3 objectives and measurements that address the science objectives outlined by the Comprehensive Demonstration Report of Phase II of CLEP. The CE-3 team has archived the initial science data, and we describe data accessibility by the science community.

极紫外相机电控单元的设计与实现

极紫外相机电控单元的设计与实现

极紫外相机电控单元检测系统的设计与实现

In order to test the function and performance of the electronic control unit of lunar-based extreme ultraviolet camera,a test system based on FPGA is designed.This system adopts FPGA as processing and control core.The system uses the communication with the computer through USB bus.And it can analyse remote data and image data which are collected by external interface of electronic control unit.Therefore,this system can complete the test of each function and each performance of the electronic unit.The result of the testing experiment of lunar-based extreme ultraviolet camera control unit and test system shows that test method of the system is accurate,and the test results are correct and effective.Because it has been fully used during the development of extreme ultraviolet camera,this test system played a great important role on the smooth degree of designing process in the program,which has the features of practical,efficient and portable.

The Chang’e-3 lander and rover mission to the Moon

The Chang’e-3 (CE-3) lander and rover mission to the Moon was an intermediate step in China’s lunar exploration program, which will be followed by a sample return mission. The lander was equipped with a number of remote-sensing instruments including a pair of cameras (Landing Camera and Terrain Camera) for recording the landing process and surveying terrain, an extreme ultraviolet camera for monitoring activities in the Earth’s plasmasphere, and a first-ever Moon-based ultraviolet telescope for astronomical observations. The Yutu rover successfully carried out close-up observations with the Panoramic Camera, mineralogical investigations with the VIS-NIR Imaging Spectrometer, study of elemental abundances with the Active Particle induced X-ray Spectrometer, and pioneering measurements of the lunar subsurface with Lunar Penetrating Radar. This special issue provides a collection of key information on the instrumental designs, calibration methods and data processing procedures used by these experiments with a perspective of facilitating further analyses of scientific data from CE-3 in preparation for future missions.

Development and calibration of the Moon-based EUV camera for Chang'e-3

The process of development and calibration for the first Moon-based extreme ultraviolet (EUV) camera to observe Earth's plasmasphere is introduced and the design, test and calibration results are presented. The EUV camera is composed of a multilayer film mirror, a thin film filter, a photon-counting imaging detector, a mechanism that can adjust the direction in two dimensions, a protective cover, an electronic unit and a thermal control unit. The center wavelength of the EUV camera is 30.2 nm with a bandwidth of 4.6 nm. The field of view is 14.7° with an angular resolution of 0.08°, and the sensitivity of the camera is 0.11 count s−1 Rayleigh−1. The geometric calibration, the absolute photometric calibration and the relative photometric calibration are carried out under different temperatures before launch to obtain a matrix that can correct geometric distortion and a matrix for relative photometric correction, which are used for in-orbit correction of the images to ensure their accuracy.

Data processing and initial results from the CE-3 Extreme Ultraviolet Camera

The Extreme Ultraviolet Camera (EUVC) onboard the Chang'e-3 (CE-3) lander is used to observe the structure and dynamics of Earth's plasmasphere from the Moon. By detecting the resonance line emission of helium ions (He+) at 30.4 nm, the EUVC images the entire plasmasphere with a time resolution of 10 min and a spatial resolution of about 0.1 Earth radius (RE) in a single frame. We first present details about the data processing from EUVC and the data acquisition in the commissioning phase, and then report some initial results, which reflect the basic features of the plasmasphere well. The photon count and emission intensity of EUVC are consistent with previous observations and models, which indicate that the EUVC works normally and can provide high quality data for future studies.

Preface: The Chang'e-3 lander and rover mission to the Moon

The Chang'e-3 (CE-3) lander and rover mission to the Moon was an intermediate step in China's lunar exploration program, which will be followed by a sample return mission. The lander was equipped with a number of remote-sensing instruments including a pair of cameras (Landing Camera and Terrain Camera) for recording the landing process and surveying terrain, an extreme ultraviolet camera for monitoring activities in the Earth's plasmasphere, and a first-ever Moon-based ultraviolet telescope for astronomical observations. The Yutu rover successfully carried out close-up observations with the Panoramic Camera, mineralogical investigations with the VIS-NIR Imaging Spectrometer, study of elemental abundances with the Active Particle-induced X-ray Spectrometer, and pioneering measurements of the lunar subsurface with Lunar Penetrating Radar. This special issue provides a collection of key information on the instrumental designs, calibration methods and data processing procedures used by these experiments with a perspective of facilitating further analyses of scientific data from CE-3 in preparation for future missions.

The Design and Implementation of Data Sampling and Processing System of EUV Camera Based on FPGA

The FPGA is applied to the Extreme Ultraviolet camera (EUV) in the emerging aerospace applications. Firstly, the imaging principle of the EUV camera is analyzed, and the FPGA type is selected. Secondly, the data collection module is designed and the original data correction and coordinate conversion algorithm is researched. Finally, the simulation results indicate that the method which is used for this paper greatly improves the dependability and stability at the cost of the small speed loss.

月基极紫外相机图像采集与实时显示系统

In order to collect scientific data of lunar-based extreme ultraviolet camera,generate images,and display these images in real-time,a display system of lunar-based extreme ultraviolet camera is designed.This system adopts FPGA of XILINX Virtex II series as the image acquisition,processing and control core.It has the functions of receiving scientific data,generating and storing the image data,as well as controlling USB interface.The system can communicate with extreme ultraviolet camera based on RS-422 interface,and receive scientific data by LVDS interface.The image data is transmitted to computer through USB bus.And the computer can generate images and display these images in real-time.Imaging experiment,using this system and the extreme ultraviolet camera,has been done.The result of this experiment shows that the system can correctly collect scientific data,generate image data and display image when the photon counting rate is 66 kcps.