Results of measurements of the analyzing powers for polarized neutrons on C, CH <inf>2</inf> and Cu targets for momenta between 3 and 4.2 GeV/c

The analyzing powers for neutron charge exchange nA → pX reactions on nuclei have been measured on C, CH2 and Cu targets at incident neutron momenta 3.0 - 4.2 GeV/c by detecting one charged particle in forward direction. The polarized neutron measurements are the first of their kind. The experiment was performed using the Nuclotron accelerator in JINR Dubna, where polarized neutrons and protons were obtained from breakup of a polarized deuteron beam which has a maximum momentum of 13 GeV/c. The polarimeter ALPOM2 was used to obtain the analyzing power dependence on the transverse momentum of the final-state nucleon. These data have been used to estimate the figure of merit of a proposed experiment at Jefferson Laboratory to measure the recoiling neutron polarization in the quasi-elastic 2H(e, e'n) reaction, which yields information on the charge and magnetic elastic form factors of the neutron

Capacities of TEC measurements by the low-cost GNSS receiver based on the u-blox ZED-F9P for ionospheric research

A prototype of a low-cost GNSS receiver assembled on base of the u-blox ZED-F9P module is described in the paper. The original low-cost GNSS receiver (OGNSS-R) allows made the parallel registration of 184 channels in the entire frequency range (1176 1610 MHz) of the main GNSS (GPS, GLONASS, Galileo, Beidou) and recording raw data of carrier-phase, pseudorange (code) and signal strength measurements. The obtained data processing allows to calculate the slant total electron content (TEC), TEC variations and other most popular TEC-based indices of ionospheric activity. The comparative studies of these parameters and similar parameters obtained by simultaneous measurements on the professional geodetic GNSS receiver Trimble Alloy (KZN2 station of the IGS network) were preformed. The analysis showed the median value of the signal strength at the L1 frequency for the KZN2 station are 8% higher than that at the low-cost GNSS receiver based on the u-blox ZED-F9P module (KZN2-48.75 dBHz; OGNSS-R - 45dBHz). For the L2 frequency that difference is less than 2% (KZN2-49.4 dBHz; OGNSS-R - 48.5 dBHz). The median levels of relative slant TEC and TEC-based indexes of the ionospheric activity obtained by the Trimble Alloy receiver at KZN2 station are 2550% lower than for the u-blox ZED-F9P receiver. Thus, the using of starter kits such as the simpleRTK2b debug board based on the u-blox ZED-F9P module described in the paper, is really actual for creating a permanent network of GNSS-stations and/or for carrying out field measurements in experimental campaigns

Comparison study of technical characteristics of low-cost multi-band gnss modules in solving the problem of measuring the total electron content of the ionosphere

A short overview of two low-cost modern GNSS modules allowing parallel obtaining of raw GNSS data at two frequencies for the GPS, GLONASS, Galileo, BeiDou is presented. These modules are appreciably cheaper than the professional GNSS devices available on the market. Using a Xiaomi Mi 8 android smartphone equipped with a dual-frequency GNSS module BCM47755 and an original GNSS receiver based on the u-blox ZED-F9P module raw GNSS data were recorded. For carrying out a comparison study the data obtained by the IGS KZN2 station equipped with the Trimble Alloy professional geodetic GNSS receiver and the Trimble TRM 59800 antenna were used as reference. Results of comparison analysis of technical characteristics of these modules for solving the problem of total electron content obtaining of the ionosphere by the measurements of two-frequency phase combinations at frequencies $\mathrm{L}1+\mathrm{L}2$ and $\mathrm{L}1+\mathrm{L}5$ are described in the paper

Simultaneous Measurements of Variations in the Artificial Airglow and the Total Electron Content of the Ionosphere Caused by Powerful Radio Waves of "Sura'' Facility

The results of simultaneous observations of variations in the artificial airglow in the red line of the optical spectrum of atomic oxygen (630 nm) and the total electron content (TEC) of the ionosphere measured along the propagation paths of the navigation satellites signal caused by the powerful HF radio emission of ``Sura'' facility on March 12, 2013 have been described in this paper. The observations of the disturbed region structure have allowed a comparison of the position of large-scale inhomogeneities of the electron density and the areas of artificial airglow generation. For comparison of variations in TEC and the artificial airglow, the following steps have been performed: Removing the regular trend brought by satellite motion from the time dependence of TEC; Spatial reference and timing of the night sky portraits received by a CCD camera and drawing of the satellite trajectory on these images; Enhancement of the spots of artificial airglow on the portraits of the night sky; Calculation of the average intensity of airglow from the image area (11 11 pixels) corresponding to the location of the satellite in time of the night sky shooting. Based on the joint analysis of the data, it has been found that the TEC level is decreased for 60% and the intensity of airglow in the red line of the optical spectrum of atomic oxygen is increased for 35% when the pumping wave is turned on. Furthermore, it has been shown that the strongest plasma waves accelerating electrons to the excitation potential of optical levels are generated in the region of low electron concentration as the antenna pattern of ``Sura`` facility is inclined at an angle of to the magnetic zenith. These results will allow applying the corrections to the description of the electron acceleration mechanism up to the levels of optical excitation of atomic oxygen

The method of plotting a spatial distribution pattern of the total electron content in the region of artificial airglow of the ionosphere

The method of plotting a spatial distribution pattern of the total electron content (TEC) in the region of artificial airglow of the ionosphere in the red line of the optical spectrum (λ = 630 nm) was developed during the experiments on disturbances of the ionosphere by powerful radio emission of the SURA facility. To test the method, a measurement session on August 29, 2016 from 18:40 to 20:10 UTC, i.e., when the ionospheric and weather conditions varied slightly and allowed simultaneous optical measurements of the artificial airglow of the ionosphere from two spatially separated sites (Vasilsursk near the SURA facility and Magnitka lying ∼ 170 km East of the SURA facility), was selected. As a result of the simultaneous optical measurements, the area of artificial airglow was plotted in a three-dimensional projection and the spatial position of the disturbed region of the ionosphere stimulated by the powerful radio emission of the SURA facility was determined. The method of plotting a spatial pattern of the electron density distribution in the disturbed region of the ionosphere is based on a joint analysis of variations in the TEC on the radio paths “navigation satellite – ground receiving site” for a number of receiving stations of the global navigation satellite systems located within a radius of ∼ 160 km from the SURA facility. By using this method, the values of electron density variations for different spatial cross-sections of the disturbed region of the ionosphere can be obtained. The joint analysis of the experimental data carried out with the help of the method under consideration showed that in the field of the powerful radio wave a disturbed region with the complex structure formed along the magnetic field lines. Plasma inhomogeneities with an increased electron density occurred at the boundaries of the region with a reduced electron concentration. The difference ∆Ne/Ne at the boundaries of the disturbed region, i.e., between the regions with increased and decreased electron density, might reach 10%. The size of the disturbed region is l⊥ ≈ 45 ÷ 60 km across and l|| ≥ 70 km along the Earth's magnetic field lines

Dynamic Changes of the Ionospheric Artificial Airglow Region Caused by High-Power Radio Waves Based on a Joint Analysis of Night-Sky Snapshots in the 630 nm Line and Total Electron Content Variation Maps

© 2020, Springer Science+Business Media, LLC, part of Springer Nature. We describe a method for joint analysis of the night-sky snapshots and total electron content (TEC) variation maps and present a dynamic spatiotemporal configuration of the TEC variation intensity in the ionospheric airglow region in the red line of atomic oxygen (λ = 630 nm) stimulated by high-power radio waves from the Sura facility. The measurements were performed on the 29th of August, 2016. Two-dimensional TEC variation maps were plotted according to a network of 30 GNSS stations located within a radius of 700 km from the Sura heater. It is shown that the region of the maximum brightness of the artificial ionospheric airglow spot is spatially localized in the region of the minimum intensity of TEC variations, while the region of the maximum intensity of TEC variations corresponds to the region of the minimum brightness of the artificial airglow spot. Quantitative estimates for a cavity with reduced electron density in the artificial airglow region, which forms after the Sura pump wave is switched on, vary in the range ΔNe/Ne ≈ 4–9%, where Ne is the electron density and ΔNe is its variation in the cavity. The proposed experimental technique eliminates the limitations associated with the need for a navigation satellite to flyby directly over the main lobe of the Sura antenna pattern, which significantly increases the chances of successful simultaneous measurements of TEC variations and artificial ionospheric airglow in the 630 nm line

The method of plotting a spatial distribution pattern of the total electron content in the region of artificial airglow of the ionosphere

The method of plotting a spatial distribution pattern of the total electron content (TEC) in the region of artificial airglow of the ionosphere in the red line of the optical spectrum (λ = = 630 nm) was developed during the experiments on disturbances of the ionosphere by powerful radio emission of the SURA facility. To test the method, a measurement session on August 29, 2016 from 18:40 to 20:10 UTC, i.e., when the ionospheric and weather conditions varied slightly and allowed simultaneous optical measurements of the artificial airglow of the ionosphere from two spatially separated sites (Vasilsursk near the SURA facility and Magnitka lying ∼ 170 km East of the SURA facility), was selected. As a result of the simultaneous optical measurements, the area of artificial airglow was plotted in a three-dimensional projection and the spatial position of the disturbed region of the ionosphere stimulated by the powerful radio emission of the SURA facility was determined. The method of plotting a spatial pattern of the electron density distribution in the disturbed region of the ionosphere is based on a joint analysis of variations in the TEC on the radio paths “navigation satellite – ground receiving site” for a number of receiving stations of the global navigation satellite systems located within a radius of ∼ 160 km from the SURA facility. By using this method, the values of electron density variations for different spatial cross-sections of the disturbed region of the ionosphere can be obtained. The joint analysis of the experimental data carried out with the help of the method under consideration showed that in the field of the powerful radio wave a disturbed region with the complex structure formed along the magnetic field lines. Plasma inhomogeneities with an increased electron density occurred at the boundaries of the region with a reduced electron concentration. The difference ∆Ne /Ne at the boundaries of the disturbed region, i.e., between the regions with increased and decreased electron density, might reach 10%. The size of the disturbed region is l⊥ ≈ 45 ÷ 60 km across and l‖ > 70 km along the Earth’s magnetic field lines

Measurement of neutron and proton analyzing powers on CC, CHCH, CH2CH_2 and CuCu targets in the momentum region 3-4.2 GeV/c

International audienceThe analyzing powers for proton elastic scattering (\varvec{p} A\rightarrow pX) and neutron charge exchange (\varvec{n} A\rightarrow p X) reactions on nuclei have been measured on C, CH, $CH_2$ and Cu targets at incident neutron momenta 3.0–4.2 GeV/c by detecting one charged particle in forward direction. The polarized neutron measurements are the first of their kind. The experiment was performed using the Nuclotron accelerator in JINR Dubna, where polarized neutrons and protons were obtained from break-up of a polarized deuteron beam which has a maximum momentum of 13 GeV/c. The polarimeter ALPOM2 was used to obtain the analyzing power dependence on the transverse momentum of the final-state nucleon. These data have been used to estimate the figure of merit of a proposed experiment at Jefferson Laboratory to measure the recoiling neutron polarization in the quasi-elastic ^2H(\varvec{e},e'\varvec{n}) reaction, which yields information on the charge and magnetic elastic form factors of the neutron