2,531 research outputs found

    The Anomalous Temporal Behaviour of Broadband Lyα\alpha Emission During Solar Flares From SDO/EVE

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    Despite being the most prominent emission line in the solar spectrum, there has been a notable lack of studies devoted to variations in Lyα\alpha emission during solar flares in recent years. However, the few examples that do exist have shown Lyα\alpha emission to be a substantial radiator of the total energy budget of solar flares (on the order of 10%). It is also a known driver of fluctuations in earth's ionosphere. The EUV Variability Experiment (EVE) onboard the Solar Dynamics Observatory now provides broadband, photometric Lyα\alpha data at 10 s cadence with its Multiple EUV Grating Spectrograph-Photometer (MEGS-P) component, and has observed scores of solar flares in the 5 years since it was launched. However, the MEGS-P time profiles appear to display a rise time of tens of minutes around the time of the flare onset. This is in stark contrast to the rapid, impulsive increase observed in other intrinsically chromospheric features (Hα\alpha, Lyβ\beta, LyC, C III, etc.). Furthermore, the emission detected by MEGS-P peaks around the time of the peak of thermal soft X-ray emission, rather than during the impulsive phase when energy deposition in the chromosphere - often assumed to be in the form of nonthermal electrons - is greatest. Given that spectrally-resolved Lyα\alpha observations during flares from SORCE/SOLSTICE peak during the impulsive phase as expected, this suggests that the atypical behaviour of MEGS-P data is a manifestation of the broadband nature of the observations. This could imply that other lines and/or continuum emission that becomes enhanced during flares could be contributing to the passband. Users are hereby urged to exercise caution when interpreting broadband Lyα\alpha observations of solar flares. Comparisons have also been made with other broadband Lyα\alpha photometers such as PROBA2/LYRA and GOES/EUVS-E.Comment: Submitted to A&A Research Notes, 5 pages 4 figure

    The genera and species of the tridenchthoniidae (dithidae) a family of the Arachnid order chelonethida

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    journal articleIn 1931, J. C. Chamberlin published an extensive treatise on the comparative external morphology and higher classification of the Chelonethida (pseudoscorpions or false scorpions).2 At that time it was the purpose to follow this work with a second volume dealing with the generic classification of the order in the same way as that contribution dealt with families and superfamilies

    Suborbital Platforms as a Tool for a Symbiotic Relationship Between Scientists, Engineers, and Students

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    Sounding rockets started in-situ space experimentation over 60 years ago with scientific experiments replacing warheads on captured V- 2 German rockets. Prior to this, and still today, suborbital platforms such as airplanes and high-altitude balloons have provided advantageous remote sensing observations advancing many areas of Earth and Space science. There is still a place for first-rate science in both stand-alone missions as well as providing complimentary measurements to the larger orbital missions. Along with the aforementioned science, the cost effectiveness and development times provided by sub-orbital platforms allows for perfect hands-on and first rate educational opportunities for undergraduate and graduate students. This talk will give examples and discuss the mutually beneficial opportunities that scientists and students obtain in development of suborbital missions. Also discussed will be how the next generation of space vehicles should help eliminate the number one obstacle to these programs - launch opportunities

    New Observations of Solar Plasma Variability from the Solar Dynamics Observatory (SDO)

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    The launch of the Solar Dynamics Observatory (SDO) in February 2010 now allows for continuous observations of the Sun on all times scales from seconds to years. The variations in the solar plasma on these time scales cause significant deviations in the Earth and space environments on similar time scales, such as affecting the densities and composition of particular atoms, molecules, and ions in the atmospheres of Earth and other planets. Presented and discussed will be examples of initial results from SDO that show how different temperature plasmas (from 50,OOOK to 20MK+), corresponding to different solar features in the solar atmosphere, evolve and change during solar eruptive events. The presentation will emphasize how the Solar Dynamics Observatory (SDO), the first satellite in NASA's Living with a Star program, has already improved upon current observations and how it will continue provide further insights into the variable Sun and its Heliospheric influence

    Solar Plasma Variability Observations from the Solar Dynamics Observatory

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    The launch of the Solar Dynamics Observatory (SDO) in February 2010 allows for continuous observations of the Sun on all times scales from seconds to years. These variations in the solar plasma cause significant deviations in the Earth and space environments on similar time scales, such as affecting the atmospheric densities and composition of particular atoms, molecules, and ions in the atmospheres of the Earth and other planets. Presented and discussed will be examples of initial results using the data from SDO that show how we can trace the origins of solar activity from inside the Sun using different wavelengths, and therefore different temperatures (from 50,OOOK to 20MK+) that cover the atmosphere and plasma temperature range of the solar atmosphere. The presentation will emphasize how the Solar Dynamics Observatory (SDO), the first satellite in NASA's Living with a Star program, is going to improve upon current observations and provide further insights into the variable Sun and its Heliospheric influence

    FISM 2.0: Improved Spectral Range, Resolution, and Accuracy

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    The Flare Irradiance Spectral Model (FISM) was first released in 2005 to provide accurate estimates of the solar VUV (0.1-190 nm) irradiance to the Space Weather community. This model was based on TIMED SEE as well as UARS and SORCE SOLSTICE measurements, and was the first model to include a 60 second temporal variation to estimate the variations due to solar flares. Along with flares, FISM also estimates the tradition solar cycle and solar rotational variations over months and decades back to 1947. This model has been highly successful in providing driving inputs to study the affect of solar irradiance variations on the Earth's ionosphere and thermosphere, lunar dust charging, as well as the Martian ionosphere. The second version of FISM, FISM2, is currently being updated to be based on the more accurate SDO/EVE data, which will provide much more accurate estimations in the 0.1-105 nm range, as well as extending the 'daily' model variation up to 300 nm based on the SOLSTICE measurements. with the spectral resolution of SDO/EVE along with SOLSTICE and the TIMED and SORCE XPS 'model' products, the entire range from 0.1-300 nm will also be available at 0.1 nm, allowing FISM2 to be improved a similar 0.1nm spectral bins. FISM also will have a TSI component that will estimate the total radiated energy during flares based on the few TSI flares observed to date. Presented here will be initial results of the FISM2 modeling efforts, as well as some challenges that will need to be overcome in order for FISM2 to accurately model the solar variations on time scales of seconds to decades

    Circular 9

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    In Alaska, as in every other agricultural area of the world, insect pests compete in many way with the farmer for the fruit of his labors. Under certain conditions many plants may be killed or consumed outright. More frequently the developing plants are weakened or stunted so that yields are reduced or quality is impaired. Insects also transmit and spread many diseases to which crops are subject. Finally, the mere presence of insects in or on the harvested crops, or the persistence of injuries inflicted earlier, reduces or destroys the quality and marketability of the product. Alaskan farmers and gardeners are fortunate that the number of insects injurious to their agriculture is at present very limited. However, as agriculture develops, as crops are diversified and expanded, and as quality standards rise, more and more insects are likely to become of economic importance, and thus require the application of improved methods of control.In cooperation with the Office of Experiment Stations and the Bureau of Entomology and Plant Quarantine, Agricultural Research AdministrationIntroduction -- Precautions to be taken with insecticides -- Common and scientific names of important insects -- Cutworms: Alaskan species, Nature of damage, Food-plant preferences, Life history, Seasonal sequence of important cutworms in the Matanuska Valley, Natural enemies, Economic importance of Alaskan cutworms with reference to control practices, Recommended practices for cutworm control -- Root maggots: Alaskan root maggots and their food-plant preferences, Life history and seasonal development, Seasonal sequence at Matanuska, Natural enemies, Nature and severity of damage, Plant resistance to root maggot damage, Suggestions for control on cole crops, Crop rotation and other agronomic practices to reduce turnip maggot damage, Suberization of potato seed pieces for protection against the seed-corn maggo

    The Genera and Species of the Hyidae a family of the arachnid order chelonethida

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    journal articleThis is the second contribution toward a revision of the generic classification of the Chelonethida. The nature and scope of this proposed work has been discussed in the first paper of the series dealing with the Tridenchthoniidae (J. C. and R. V. Chamberlin, Utah Univ. Bui. Biol. Ser., V, Vol. 9, no. 2, 67 pp. 1945) ,2

    Reconstructing the Solar VUV Irradiance Over the Past 60 Years

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    Actual observations of the solar spectral irradiance are extremely limited on climate time scales; therefore, various empirical models use solar proxies to reconstruct the actual output of the Sun over long time scales. The Flare Irradiance Spectral Model (FISM) is an empirical model of the solar irradiance spectrum from 0.1 to 190 nm at 1 nm spectral resolution and on a I-minute time cadence. The goal of FISM is to provide accurate solar spectral irradiances over the vacuum ultraviolet (VUV: 0-200 nm) range as input for ionospheric and thermospheric. A brief overview of the proxies used in the FISM model will be given, and also discussed is how the Solar Dynamics Observatory (SDO) EUV Variability Experiment (EVE) will contribute to improving FISM estimates and its accuracies. Also presented will be a discussion of other solar irradiance proxies and measurements, and their associated uncertainties, used for solar spectral reconstructions

    Solar EUV Variability from FISM and SDO/EVE During Solar Minimum, Active, and Flaring Time Periods

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    The Living With a Star (LWS) Focus Science Team has identified three periods of different solar activity levels for which they will be determining the Earth's Ionosphere and Thermosphere response. Not only will the team be comparing individual models (e.g. FLIP, T1MEGCM, GLOW) outcome driven by the various levels of solar activity, but the models themselves will also be compared. These models all rely on the input solar EUV (0.1 -190 nm) irradiance to drive the variability. The Flare Irradiance Spectral Model (FISM) and the EUV Variability Experiment (EVE) onboard provide the Solar Dynamics Observatory (SDO) provide the most accurate quantification of these irradiances. Presented and discussed are how much the solar EUV irradiance changes during these three scenarios, both as a function of activity and wavelength
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