scholarly journals Design of Multifunctional Mesosphere-Ionosphere Sounding System and Preliminary Results

Sensors ◽  
2020 ◽  
Vol 20 (9) ◽  
pp. 2664
Author(s):  
Tongxin Liu ◽  
Guobin Yang ◽  
Zhengyu Zhao ◽  
Yi Liu ◽  
Chen Zhou ◽  
...  
Keyword(s):  
Electron Density ◽  
Pulse Compression ◽  
Middle Atmosphere ◽  
Electron Density Profile ◽  
System Structure ◽  
Coupling Mechanism ◽  
Antenna Structure ◽  
Miniaturized Antenna ◽  
Ionospheric Sounding ◽  
Mf Radar

This paper describes a novel sounding system for which the functions of the medium frequency (MF) radar and the ionosonde are integrated on the same hardware platform and antenna structure, namely the middle atmosphere-ionosphere (MAI) system. Unlike the common MF radar, MAI system adopts the pseudo-random (PRN) phase-coded modulation technology, which breaks the limitation of the traditional monopulse mode. Through the pulse compression, only a small peak power is needed to achieve the signal-to-noise ratio (SNR) requirement. The excellent anti-jamming performance is also very suitable for the ionospheric sounding. One transmitting and six receiving modes are adopted for the MF sounding. While neglecting the structure of the T/R switches, the coupling interference between the transmitter and the receiver may also be avoided. Moreover, by employing a miniaturized antenna array composed of progressive-wave antennas for the MF receiving and ionospheric sounding, the MAI system takes account of the requirements of the inversion algorithms of MF radar and the large bandwidth need for the ionospheric sounding concurrently. Such an antenna structure can also greatly simplify the system structure and minimize the difficulty of deployment. The experiments verified the availability of the system scheme and its engineering application significance. Through further analysis of the sounding data, the wind field of the mesosphere, the electron density of D layer and electron density profile from layers E to F were obtained at the identical location. The capability of MAI system can play an important role in studying the interaction and coupling mechanism between the mesosphere and ionosphere.

Estimation of the electron density profile in the D region from rocket measurement of VLF signals from a ground based transmitter

1981 ◽  
Vol 64 (11) ◽  
pp. 68-74
Author(s):  
Isamu Nagano ◽  
Masayoshi Mambo ◽  
Tetsuo Fukami ◽  
Koji Namba ◽  
Iwane Kimura
Keyword(s):  
Electron Density ◽  
Density Profile ◽  
Electron Density Profile ◽  
Rocket Measurement ◽  
D Region

scholarly journals Radial density profile and stability of capillary discharge plasma waveguides of lengths up to 40 cm

2021 ◽  
Vol 9 ◽  
Author(s):  
M. Turner ◽  
A. J. Gonsalves ◽  
S. S. Bulanov ◽  
C. Benedetti ◽  
N. A. Bobrova ◽  
...  
Keyword(s):  
Laser Pulse ◽  
Electron Density ◽  
Density Profile ◽  
Pulse Propagation ◽  
Spot Size ◽  
Capillary Discharge ◽  
Electron Density Profile ◽  
Plasma Waveguide ◽  
Wakefield Acceleration ◽  
Plasma Wakefield

Abstract We measured the parameter reproducibility and radial electron density profile of capillary discharge waveguides with diameters of 650 $\mathrm{\mu} \mathrm{m}$ to 2 mm and lengths of 9 to 40 cm. To the best of the authors’ knowledge, 40 cm is the longest discharge capillary plasma waveguide to date. This length is important for $\ge$ 10 GeV electron energy gain in a single laser-driven plasma wakefield acceleration stage. Evaluation of waveguide parameter variations showed that their focusing strength was stable and reproducible to $<0.2$ % and their average on-axis plasma electron density to $<1$ %. These variations explain only a small fraction of laser-driven plasma wakefield acceleration electron bunch variations observed in experiments to date. Measurements of laser pulse centroid oscillations revealed that the radial channel profile rises faster than parabolic and is in excellent agreement with magnetohydrodynamic simulation results. We show that the effects of non-parabolic contributions on Gaussian pulse propagation were negligible when the pulse was approximately matched to the channel. However, they affected pulse propagation for a non-matched configuration in which the waveguide was used as a plasma telescope to change the focused laser pulse spot size.

Impurity effects on trapped electron modes in tokamak plasmas with inverted electron density profile

2021 ◽  
Vol 28 (5) ◽  
pp. 052510
Author(s):  
X. R. Zhang ◽  
J. Q. Dong ◽  
H. R. Du ◽  
J. Y. Liu ◽  
Y. Shen ◽  
...  
Keyword(s):  
Electron Density ◽  
Density Profile ◽  
Electron Density Profile ◽  
Tokamak Plasmas ◽  
Impurity Effects ◽  
Trapped Electron

scholarly journals Spectral characteristics of spring arctic mesosphere dynamics

1998 ◽  
Vol 16 (12) ◽  
pp. 1607-1618 ◽  
Author(s):  
C. M. Hall ◽  
A. H. Manson ◽  
C. E. Meek
Keyword(s):  
Energy Dissipation ◽  
Middle Atmosphere ◽  
Spectral Characteristics ◽  
Turbulent Energy ◽  
Energy Dissipation Rate ◽  
Spectral Signature ◽  
Upper Limits ◽  
Waves And Tides ◽  
Signal Fading ◽  
Mf Radar

Abstract. The spring of 1997 has represented a stable period of operation for the joint University of Tromsø / University of Saskatchewan MF radar, being between refurbishment and upgrades. We examine the horizontal winds from the February to June inclusive and also include estimates of energy dissipation rates derived from signal fading times and presented as upper limits on the turbulent energy dissipation rate, ε. Here we address the periodicity in the dynamics of the upper mesosphere for time scales from hours to one month. Thus, we are able to examine the changes in the spectral signature of the mesospheric dynamics during the transition from winter to summer states.Key words. Meteorology and atmospheric dynamics (middle atmosphere dynamics; turbulence; waves and tides).

Ultrashort pulse reflectometry for electron density profile measurements

1999 ◽  
Vol 70 (1) ◽  
pp. 1038-1041 ◽  
Author(s):  
C. W. Domier ◽  
Y. Roh ◽  
N. C. Luhmann
Keyword(s):  
Electron Density ◽  
Density Profile ◽  
Ultrashort Pulse ◽  
Electron Density Profile

scholarly journals NLC and the background atmosphere above ALOMAR

2011 ◽  
Vol 11 (12) ◽  
pp. 5701-5717 ◽  
Author(s):  
J. Fiedler ◽  
G. Baumgarten ◽  
U. Berger ◽  
P. Hoffmann ◽  
N. Kaifler ◽  
...  
Keyword(s):  
Diurnal Cycle ◽  
Middle Atmosphere ◽  
Thermal State ◽  
Atmospheric Tides ◽  
Data Set ◽  
Ice Particles ◽  
Cloud Water Content ◽  
Radar Measurements ◽  
Mf Radar

Abstract. Noctilucent clouds (NLC) have been measured by the Rayleigh/Mie/Raman-lidar at the ALOMAR research facility in Northern Norway (69° N, 16° E). From 1997 to 2010 NLC were detected during more than 1850 h on 440 different days. Colocated MF-radar measurements and calculations with the Leibniz-Institute Middle Atmosphere (LIMA-) model are used to characterize the background atmosphere. Temperatures as well as horizontal winds at 83 km altitude show distinct differences during NLC observations compared to when NLC are absent. The seasonally averaged temperature is lower and the winds are stronger westward when NLC are detected. The wind separation is a robust feature as it shows up in measurements as well as in model results and it is consistent with the current understanding that lower temperatures support the existence of ice particles. For the whole 14-year data set there is no statistically significant relation between NLC occurrence and solar Lyman-α radiation. On the other hand NLC occurrence and temperatures at 83 km show a significant anti-correlation, which suggests that the thermal state plays a major role for the existence of ice particles and dominates the pure Lyman-α influence on water vapor during certain years. We find the seasonal mean NLC altitudes to be correlated to both Lyman-α radiation and temperature. NLC above ALOMAR are strongly influenced by atmospheric tides. The cloud water content varies by a factor of 2.8 over the diurnal cycle. Diurnal and semidiurnal amplitudes and phases show some pronounced year-to-year variations. In general, amplitudes as well as phases vary in a different manner. Amplitudes change by a factor of more than 3 and phases vary by up to 7 h. Such variability could impact long-term NLC observations which do not cover the full diurnal cycle.

A New Radar Signal Processing Architecture Based on Multi-Core Processor

2014 ◽  
Vol 556-562 ◽  
pp. 1618-1621
Author(s):  
Jia Liang Fan ◽  
Qiang Yang
Keyword(s):  
Signal Processing ◽  
Pulse Compression ◽  
Adaptive Beamforming ◽  
System Structure ◽  
Radar Signal ◽  
Radar Signal Processing ◽  
Test Results ◽  
Radar Systems ◽  
Multi Core Processor ◽  
Processing Architecture

Most radar systems based on the structure that contains many DSP chips. The system structure is always complex, and it is difficult to update. Nowadays, multi-core processor develops very fast. Compared with DSP chips, multi-core processor has better performance in signal processing field. In this paper, we present a signal processing architecture which based on multi-core processor. Pulse compression algorithms and PCI-E bus are discussed as two important technologies. Adaptive beamforming test results show that multi-core processor is able to achieve radar signal processing.

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