9,344 research outputs found

    Millstone Hill Thomson Scatter Results for 1972

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    During 1972, the vertically directed incoherent scatter radar at Millstone Hill (42.6°N, 71.5°W) was employed to measure electron density, electron and ion temperatures, and vertical ion velocity in the F-region over periods of 24 hours, one or two times per month. The observations spanned the height interval 200 to 900 km, approximately, and achieved a time resolution of about 30 minutes. This report presents the results of these measurements in a set of contour diagrams. For a number of the days, the spectra of the signals gathered at altitudes between 450 and 1125 km have been the subject of further analysis in an effort to determine the percentage of H[superscript +] ions present over Millstone. The results suggest that H[superscript +] ions are escaping from the F-region to the magnetosphere at a value close to the theoretical limiting flux during the daytime in all seasons. At night the flux becomes downward commencing near midnight in winter, but may remain upward throughout the night in summer

    Millstone Hill Thomson Scatter Results for 1971

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    During 1971, the incoherent scatter radar at Millstone Hill (42.6°N, 71.5°W) was employed to measure the electron density, electron and ion temperatures, and the vertical velocity of the 0[superscript +] ions in the F-region over periods of 24 hours on 20 days. The observations spanned the height interval 200 to 900 km, approximately, and achieved a time resolution of about 30 minutes. This report presents these results, after smoothing as a set of machine-drawn contour plots. The report discusses the behavior observed in 1971 in light of that seen in previous years. A significant number of days appear to have been disturbed by large traveling ionospheric disturbances. Results for the average exospheric temperature, the mean meridional, and zonal winds for 1970and 1971 derived from these incoherent scatter measurements in a separate study by B.A. Emery are summarized here for completeness. The results appear to confirm the mean wind behavior that would be predicted by the recent Mass-Spectrometer, Incoherent-Scatter (MSIS) global model for the thermosphere and support the view that interhemispheric transport of light neutral constituents (e.g., atomic oxygen) gives rise to tie anomalous seasonal behavior of the ionosphere at midlatitudes

    Millstone Hill Thomson Scatter Results for 1973

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    During 1973, the vertically-directed incoherent scatter radar at Millstone Hill (42.6°N, 71.5°W) was employed to measure electron density, electron and ion temperature and vertical ion velocity in the F-region over periods of 24 hours one or two times per month. The observations spanned the height interval 200-900 km approximately, and achieved a time resolution of about 30 minutes. This report presents the results of these measurements in a set of contour diagrams. For a number of the days, the results have been used to derive the diurnal variation of the temperature of the neutral atmosphere above 300 km (the exospheric temperature) as well as the speed of the neutral wind in the magnetic meridian plane at this altitude. These results were used to define a model for the pressure variation in the thermosphere over Millstone whose E-W variation is set by the observed temperature variation, and whose N-S variation was adjusted to reproduce the observed winds calculated by solving momentum equations for the neutral air. These results, together with similar results obtained using data gathered over the six-year period 1970-1975 have been used in a study of the seasonal and sunspot cycle variation of the mean meridional and zonal winds. Also reported are the results of a study of the effect of magnetic storms on the thermospheric winds observed over Millstone Hill

    Developing an evaluation strategy in Kashmir: assessing the impact of an arts intervention with school children in an area of conflict

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    About 1 in 6 children live in areas of conflict globally (Save the children, 2022), with significant impact on mental health, behaviour, and life outcomes (Buser et al., 2023). Research on ways to help prevent and reduce suffering is paramount, yet assessing the impact of interventions on children in the context of conflict is challenging, beset with ethical, cultural and psychometric difficulties (Newman et al., 2006). This practice report shares and reflects on the research strategy developed to evaluate the impact of an arts intervention in the Kashmir Valley, funded by an AHRC Urgency bid to help children in crisis. The study took part in a highly militarised area, where children were regularly exposed to violence, protests and resistance, and education and family life were heavily impacted by military lockdowns. When the study began (June 2020) conditions were further intensified by rising cases of coronavirus. The arts-based intervention occurred at one school and ran throughout their academic year (from August 2020). Thirty children (aged 12-15) were referred by the school to participate in a programme that was integrated into the curriculum and included a range of art activities: painting, writing, puppetry, music and performance, designed to enable expression and improve wellbeing, led by an artist and art therapist (Buser et al., 2023)

    Measurement of tensor analyzing powers in deuteron photodisintegration

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    New accurate measurement of tensor analyzing powers T20, T21 and T22 in deuteron photodisintegration has been performed. Wide-aperture non-magnetic detectors allowed to cover broad kinematic ranges in a single setup: photon energy = 25 to 600 MeV, proton emission angle in CM = 24 to 48 deg. and 70 to 102 deg. New data provide a significant improvement of a few existing measurements. The angular dependency of the tensor asymmetries in deuteron photodisintegration is extracted for the first time.Comment: 4 pages, 5 figures, submitted to Phys. Rev. Let

    Evidence for Proportionate Partition Between the Magnetic Field and Hot Gas in Turbulent Cassiopeia A

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    We present a deep X-ray observation of the young Galactic supernova remnant Cas A, acquired with the ROSAT High Resolution Imager. This high dynamic range (232 ks) image reveals low-surface-brightness X-ray structure, which appears qualitatively similar to corresponding radio features. We consider the correlation between the X-ray and radio morphologies and its physical implications. After correcting for the inhomogeneous absorption across the remnant, we performed a point by point (4" resolution) surface brightness comparison between the X-ray and radio images. We find a strong (r = 0.75) log-log correlation, implying an overall relationship of log(ΣXray)(2.21±0.05)×log(Σradio)\log(\Sigma_{_{\rm X-ray}}) \propto (2.21\pm0.05) \times \log(\Sigma_{_{\rm radio}}). This is consistent with proportionate partition (and possibly equipartition) between the local magnetic field and the hot gas --- implying that Cas A's plasma is fully turbulent and continuously amplifying the magnetic field.Comment: 8 pages with embedded bitmapped figures, Accepted by ApJ Letters 5/1/9
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