Found 13 results
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2020
Authors: Duan Die, Bowen Trevor A., Chen Christopher H. K., Mallet Alfred, He Jiansen, et al.
Title: The Radial Dependence of Proton-scale Magnetic Spectral Break in Slow Solar Wind during PSP Encounter 2
Abstract:

Magnetic field fluctuations in the solar wind are commonly observed to follow a power-law spectrum. Near proton-kinetic scales, a spectral break occurs that is commonly interpreted as a transition to kinetic turbulence. However, this transition is not yet entirely understood. By studying the scaling of the break with various plasma properties, it may be possible to constrain the processes leading to the onset of kinetic turbulence. Using data from the Parker Solar Probe, we measure the proton-scale break over a range of heliocentric distances, enabling a measurement of the transition from inertial to kinetic-scale turbulence under various plasma conditions. We find that the break frequency fb increases as the heliocentric distance r decreases in the slow solar wind following . . .
Date: 02/2020 Publisher: The Astrophysical Journal Supplement Series Pages: 55 DOI: 10.3847/1538-4365/ab672d Available at: https://iopscience.iop.org/article/10.3847/1538-4365/ab672d
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Authors: Rouillard Alexis P., Kouloumvakos Athanasios, Vourlidas Angelos, Kasper Justin, Bale Stuart, et al.
Title: Relating Streamer Flows to Density and Magnetic Structures at the Parker Solar Probe
Abstract:

The physical mechanisms that produce the slow solar wind are still highly debated. Parker Solar Probe's (PSP's) second solar encounter provided a new opportunity to relate in situ measurements of the nascent slow solar wind with white-light images of streamer flows. We exploit data taken by the Solar and Heliospheric Observatory, the Solar TErrestrial RElations Observatory (STEREO), and the Wide Imager on Solar Probe to reveal for the first time a close link between imaged streamer flows and the high-density plasma measured by the Solar Wind Electrons Alphas and Protons (SWEAP) experiment. We identify different types of slow winds measured by PSP that we relate to the spacecraft's magnetic connectivity (or not) to streamer flows. SWEAP measured high-density and highly variable plasma wh. . .
Date: 02/2020 Publisher: The Astrophysical Journal Supplement Series Pages: 37 DOI: 10.3847/1538-4365/ab579a Available at: https://iopscience.iop.org/article/10.3847/1538-4365/ab579a
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Authors: Réville Victor, Velli Marco, Panasenco Olga, Tenerani Anna, Shi Chen, et al.
Title: The Role of Alfvén Wave Dynamics on the Large-scale Properties of the Solar Wind: Comparing an MHD Simulation with Parker Solar Probe E1 Data
Abstract:

During Parker Solar Probe's first orbit, the solar wind plasma was observed in situ closer than ever before, the perihelion on 2018 November 6 revealing a flow that is constantly permeated by large-amplitude Alfvénic fluctuations. These include radial magnetic field reversals, or switchbacks, that seem to be a persistent feature of the young solar wind. The measurements also reveal a very strong, unexpected, azimuthal velocity component. In this work, we numerically model the solar corona during this first encounter, solving the MHD equations and accounting for Alfvén wave transport and dissipation. We find that the large-scale plasma parameters are well reproduced, allowing the computation of the solar wind sources at Probe with confidence. We try to understand the dynamical nature o. . .
Date: 02/2020 Publisher: The Astrophysical Journal Supplement Series Pages: 24 DOI: 10.3847/1538-4365/ab4fef Available at: https://iopscience.iop.org/article/10.3847/1538-4365/ab4fef
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2019
Authors: Ratmaya Widya, Soudant Dominique, Salmon-Monviola Jordy, Plus Martin, Cochennec-Laureau Nathalie, et al.
Title: Reduced phosphorus loads from the Loire and Vilaine rivers were accompanied by increasing eutrophication in the Vilaine Bay (south Brittany, France)
Abstract:

The evolution of eutrophication parameters (i.e., nutrients and phytoplankton biomass) during recent decades was examined in coastal waters of the Vilaine Bay (VB, France) in relation to changes in the Loire and Vilaine rivers. Dynamic linear models were used to study long-term trends and seasonality of dissolved inorganic nutrient and chlorophyll a concentrations (Chl a) in rivers and coastal waters. For the period 1997-2013, the reduction in dissolved riverine inorganic phosphorus (DIP) concentrations led to the decrease in their Chl a levels. However, while dissolved inorganic nitrogen (DIN) concentrations decreased only slightly in the Vilaine, they increased in the Loire, specifically in summer. Simultaneously, phytoplankton in the VB underwent profound changes with increase in bio. . .
Date: 04/2019 Publisher: Biogeosciences Pages: 1361 - 1380 DOI: 10.5194/bg-16-1361-201910.5194/bg-16-1361-2019-supplement Available at: https://www.biogeosciences.net/16/1361/2019/https://www.biogeosciences.net/16/1361/2019/bg-16-1361-2019.pdfhttps://www.biogeosciences.net/16/1361/2019/bg-16-1361-2019-supplement.pdf
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Authors: Le Fur I, De Wit R, Plus M, Oheix J, Derolez V, et al.
Title: Re-oligotrophication trajectories of macrophyte assemblages in Mediterranean coastal lagoons based on 17-year time-series
Abstract:

No abstract


Date: 01/2019 Publisher: Marine Ecology Progress Series Pages: 13 - 32 DOI: 10.3354/meps12814 Available at: https://www.int-res.com/abstracts/meps/v608/p13-32/https://www.int-res.com/articles/meps_oa/m608p013.pdf
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Authors: Parashar T. N., Cuesta M., and Matthaeus W. H.
Title: Reynolds Number and Intermittency in the Expanding Solar Wind: Predictions Based on Voyager Observations
Abstract:

The large-scale features of the solar wind are examined in order to predict small-scale features of turbulence in unexplored regions of the heliosphere. The strategy is to examine how system size, or effective Reynolds number Re, varies, and then how this quantity influences observable statistical properties, including intermittency properties of solar wind turbulence. The expectation based on similar hydrodynamics scalings is that the kurtosis, of the small-scale magnetic field increments, will increase with increasing Re. Simple theoretical arguments as well as Voyager observations indicate that effective interplanetary turbulence Re decreases with increasing heliocentric distance. The decrease of scale-dependent magnetic increment kurtosis with increasing heliocentric distance is ver. . .
Date: 10/2019 Publisher: The Astrophysical Journal Pages: L57 DOI: 10.3847/2041-8213/ab4a82 Available at: https://iopscience.iop.org/article/10.3847/2041-8213/ab4a82
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2018
Authors: Perrone Denise, Stansby D, Horbury T S, and Matteini L
Title: Radial evolution of the solar wind in pure high-speed streams: HELIOS revised observations
Abstract:

Spacecraft observations have shown that the proton temperature in the solar wind falls off with radial distance more slowly than expected for an adiabatic prediction. Usually, previous studies have been focused on the evolution of the solar-wind plasma by using the bulk speed as an order parameter to discriminate different regimes. In contrast, here, we study the radial evolution of pure and homogeneous fast streams (i.e. well-defined streams of coronal-hole plasma that maintain their identity during several solar rotations) by means of re-processed particle data, from the HELIOS satellites between 0.3 and 1 au. We have identified 16 intervals of unperturbed high-speed coronal-hole plasma, from three different sources and measured at different radial distances. The observations show tha. . .
Date: 03/2019 Publisher: Monthly Notices of the Royal Astronomical Society Pages: 3730 - 3737 DOI: 10.1093/mnras/sty3348 Available at: https://academic.oup.com/mnras/article/483/3/3730/5237719http://academic.oup.com/mnras/article-pdf/483/3/3730/27299782/sty3348.pdf
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Authors: Perrone Denise, Stansby D, Horbury T, and Matteini L
Title: Radial evolution of the solar wind in pure high-speed streams: HELIOS revised observations
Abstract:

Spacecraft observations have shown that the proton temperature in the solar wind falls off with radial distance more slowly than expected for an adiabatic prediction. Usually, previous studies have been focused on the evolution of the solar-wind plasma by using the bulk speed as an order parameter to discriminate different regimes. In contrast, here, we study the radial evolution of pure and homogeneous fast streams (i.e. well-defined streams of coronal-hole plasma that maintain their identity during several solar rotations) by means of re-processed particle data, from the HELIOS satellites between 0.3 and 1 au. We have identified 16 intervals of unperturbed high-speed coronal-hole plasma, from three different sources and measured at different radial distances. The observations show tha. . .
Date: 10/2018 Publisher: Monthly Notices of the Royal Astronomical Society DOI: 10.1093/mnras/sty3348 Available at: https://academic.oup.com/mnras/advance-article/doi/10.1093/mnras/sty3348/5237719http://academic.oup.com/mnras/advance-article-pdf/doi/10.1093/mnras/sty3348/27082965/sty3348.pdf
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Authors: Tsurutani Bruce T., Lakhina Gurbax S., Sen Abhijit, Hellinger Petr, Glassmeier Karl-Heinz, et al.
Title: A Review of Alfvénic Turbulence in High-Speed Solar Wind Streams: Hints From Cometary Plasma Turbulence
Abstract:

Solar wind turbulence within high-speed streams is reviewed from the point of view of embedded single nonlinear Alfvén wave cycles, discontinuities, magnetic decreases (MDs), and shocks. For comparison and guidance, cometary plasma turbulence is also briefly reviewed. It is demonstrated that cometary nonlinear magnetosonic waves phase-steepen, with a right-hand circular polarized foreshortened front and an elongated, compressive trailing edge. The former part is a form of "wave breaking" and the latter that of "period doubling." Interplanetary nonlinear Alfvén waves, which are arc polarized, have a 180° foreshortened front and with an elongated trailing edge. Alfvén waves have polarizations different from those of cometary magnetosonic waves, indicating that helicity is a durable fe. . .
Date: Jan-04-2018 Publisher: Journal of Geophysical Research: Space Physics Pages: 2458 - 2492 DOI: 10.1002/jgra.v123.410.1002/2017JA024203 Available at: https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2F2017JA024203
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2017
Authors: Bernhard Germar, Petropavlovskikh Irina, and Mayer Bernhard
Title: Retrieving vertical ozone profiles from measurements of global spectral irradiance
Abstract:

A new method is presented to determine vertical ozone profiles from measurements of spectral global (direct Sun plus upper hemisphere) irradiance in the ultraviolet. The method is similar to the widely used Umkehr technique, which inverts measurements of zenith sky radiance. The procedure was applied to measurements of a high-resolution spectroradiometer installed near the centre of the Greenland ice sheet. Retrieved profiles were validated with balloon-sonde observations and ozone profiles from the space-borne Microwave Limb Sounder (MLS). Depending on altitude, the bias between retrieval results presented in this paper and MLS observations ranges between -5 and +3 %. The magnitude of this bias is comparable, if not smaller, to values reported in the literature for the standard Dobson . . .
Date: 12/2017 Publisher: Atmospheric Measurement Techniques Pages: 4979 - 4994 DOI: 10.5194/amt-10-4979-2017 Available at: https://www.atmos-meas-tech.net/10/4979/2017/https://www.atmos-meas-tech.net/10/4979/2017/amt-10-4979-2017.pdf
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2015
Authors: Good S. W., Forsyth R. J., Raines J. M., Gershman D. J., Slavin J. A., et al.
Title: RADIAL EVOLUTION OF A MAGNETIC CLOUD: MESSENGER , STEREO , AND VENUS EXPRESS OBSERVATIONS
Abstract:

The Solar Orbiter and Solar Probe Plus missions will provide observations of magnetic clouds closer to the Sun than ever before, and it will be good preparation for these missions to make full use of the most recent in situ data sets from the inner heliosphere—namely, those provided by MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) and Venus Express—for magnetic cloud studies. We present observations of the same magnetic cloud made by MESSENGER at Mercury and later by Solar TErrestrial RElations Observatory-B (STEREO-B), while the spacecraft were radially aligned in 2011 November. Few such radial observations of magnetic clouds have been previously reported. Estimates of the solar wind speed at MESSENGER are also presented, calculated through the applicati. . .
Date: 07/2015 Publisher: The Astrophysical Journal Pages: 177 DOI: 10.1088/0004-637X/807/2/177 Available at: http://stacks.iop.org/0004-637X/807/i=2/a=177?key=crossref.a1b49ae2196cca72b5d1ec280eba0793
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1975
Authors: Plus R., and Lutz M.
Title: Resonance Raman Scattering of Mesoporphyrin IX Dimethylester in Solution
Abstract:

Resonance Raman spectra of Mesoporphyrin IX dimethylester in solution were obtained using various wavelengths in the region of electronic band IV. Vibrational data, as well as variations in the depolarization ratios and the band intensities with excitation wavelengths were compared to those previously obtained for porphin. The new data provide confirmation of the existence of three, most probably purely electronic transitions in band IV of both Mesoporphyrin IX dimethylester and porphin.


Date: 01/1975 Publisher: Spectroscopy Letters Pages: 119 - 139 DOI: 10.1080/00387017508067314 Available at: https://www.tandfonline.com/doi/full/10.1080/00387017508067314https://www.tandfonline.com/doi/pdf/10.1080/00387017508067314
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1974
Authors: Plus R., and Lutz M.
Title: Resonance Raman Spectroscopy of Porphin
Abstract:

We report and discuss Raman spectra of porphin. These were obtained by resonance effect, irradiating in the electronic band IV. Unexpected variations of vibrational band intensities and depolarization ratios were recorded on changing the excitation wavelength. Some implications on the symmetry types of the vibrations are discussed. Results are compared with current data from quasi-linear electronic spectra.


Date: 01/1974 Publisher: Spectroscopy Letters Pages: 133 - 145 DOI: 10.1080/00387017408067229 Available at: https://www.tandfonline.com/doi/full/10.1080/00387017408067229https://www.tandfonline.com/doi/pdf/10.1080/00387017408067229
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