Found 123 results
Author Title Type [ Year(Asc)]
2017
Authors: Meyer-Vernet N., Issautier K., and Moncuquet M.
Title: Quasi-thermal noise spectroscopy: The art and the practice
Abstract:

Quasi-thermal noise spectroscopy is an efficient tool for measuring in situ macroscopic plasma properties in space, using a passive wave receiver at the ports of an electric antenna. This technique was pioneered on spinning spacecraft carrying very long dipole antennas in the interplanetary medium—like ISEE-3 and Ulysses—whose geometry approached a "theoretician's dream." The technique has been extended to other instruments in various types of plasmas on board different spacecraft and will be implemented on several missions in the near future. Such extensions require different theoretical modelizations, involving magnetized, drifting, or dusty plasmas with various particle velocity distributions and antennas being shorter, biased, or made of unequal wires. We give new analytical app. . .
Date: 08/2017 Publisher: Journal of Geophysical Research: Space Physics Pages: 7925 - 7945 DOI: 10.1002/2017JA024449 Available at: http://doi.wiley.com/10.1002/2017JA024449http://onlinelibrary.wiley.com/wol1/doi/10.1002/2017JA024449/fullpdf
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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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Authors: Pulupa M., Bale S. D., Bonnell J. W., Bowen T. A., Carruth N., et al.
Title: The solar probe plus radio frequency spectrometer: Measurement requirements, analog design, and digital signal processing
Abstract:

The Radio Frequency Spectrometer (RFS) is a two-channel digital receiver and spectrometer, which will make remote sensing observations of radio waves and in situ measurements of electrostatic and electromagnetic fluctuations in the solar wind. A part of the FIELDS suite for Solar Probe Plus (SPP), the RFS is optimized for measurements in the inner heliosphere, where solar radio bursts are more intense and the plasma frequency is higher compared to previous measurements at distances of 1 AU or greater. The inputs to the RFS receiver are the four electric antennas mounted near the front of the SPP spacecraft and a single axis of the SPP search coil magnetometer (SCM). Each RFS channel selects a monopole or dipole antenna input, or the SCM input, via multiplexers. The primary data products. . .
Date: 03/2017 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2016JA023345 Available at: https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2016JA023345
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Authors: Kasper J. C., Klein K. G., Weber T., Maksimovic M., Zaslavsky A., et al.
Title: A Zone of Preferential Ion Heating Extends Tens of Solar Radii from the Sun
Abstract:

The extreme temperatures and nonthermal nature of the solar corona and solar wind arise from an unidentified physical mechanism that preferentially heats certain ion species relative to others. Spectroscopic indicators of unequal temperatures commence within a fraction of a solar radius above the surface of the Sun, but the outer reach of this mechanism has yet to be determined. Here we present an empirical procedure for combining interplanetary solar wind measurements and a modeled energy equation including Coulomb relaxation to solve for the typical outer boundary of this zone of preferential heating. Applied to two decades of observations by the Wind spacecraft, our results are consistent with preferential heating being active in a zone extending from the transition region in the low. . .
Date: 11/2017 Publisher: The Astrophysical Journal Pages: 126 DOI: 10.3847/1538-4357/aa84b1 Available at: http://stacks.iop.org/0004-637X/849/i=2/a=126?key=crossref.a4fda357a12d19fd2ad1aa8a3897c78f
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2016
Authors: Tracy Patrick J., Kasper Justin C., Raines Jim M., Shearer Paul, Gilbert Jason A., et al.
Title: Constraining Solar Wind Heating Processes by Kinetic Properties of Heavy Ions
Abstract:

We analyze the heavy ion components (A >4 amu ) in collisionally young solar wind plasma and show that there is a clear, stable dependence of temperature on mass, probably reflecting the conditions in the solar corona. We consider both linear and power law forms for the dependence and find that a simple linear fit of the form Ti/Tp=(1.35 ±.02 )mi/mp describes the observations twice as well as the equivalent best fit power law of the form Ti/Tp=(mi/mp) 1.07 ±.01 . Most importantly we find that current model predictions based on turbulent transport and kinetic dissipation are in agreement with observed nonthermal heating in intermediate collisional age plasma for m /q <3.5 , but are . . .
Date: 06/2016 Publisher: Physical Review Letters DOI: 10.1103/PhysRevLett.116.255101 Available at: https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.116.255101
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Authors: Malaspina David M., Ergun Robert E., Bolton Mary, Kien Mark, Summers David, et al.
Title: The Digital Fields Board for the FIELDS instrument suite on the Solar Probe Plus mission: Analog and digital signal processing
Abstract:

The first in situ measurements of electric and magnetic fields in the near-Sun environment (< 0.25 AU from the Sun) will be made by the FIELDS instrument suite on the Solar Probe Plus mission. The Digital Fields Board (DFB) is an electronics board within FIELDS that performs analog and digital signal processing, as well as digitization, for signals between DC and 60 kHz from five voltage sensors and four search coil magnetometer channels. These nine input signals are processed on the DFB into 26 analog data streams. A specialized application-specific integrated circuit performs analog to digital conversion on all 26 analog channels simultaneously. The DFB then processes the digital data using a field programmable gate array (FPGA), generating a variety of data products, including dig. . .
Date: 06/2016 Publisher: Journal of Geophysical Research: Space Physics Pages: 5088 - 5096 DOI: 10.1002/2016JA022344 Available at: http://doi.wiley.com/10.1002/2016JA022344http://onlinelibrary.wiley.com/wol1/doi/10.1002/2016JA022344/fullpdf
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Authors: Fox Nicola J., and McComas David J.
Title: Editorial: Topical Volume on Developing the Solar Probe Plus Mission
Abstract:

The Solar Probe Plus mission is a remarkable and historic step in the exploration of humankind. We have visited all of the planets and a number of other smaller moons and bodies; we have explored the magnetospheres, not just of Earth but also of all the planets; and we have explored our heliosphere and even flown a spacecraft beyond its boundary and into interstellar space itself. However, only with the launch of Solar Probe Plus will we actually visit our own star—the Sun—repeatedly traveling to within 9 solar radii (R S  RS ) of its surface (10R S  10RS heliocentric) and directly through its corona. From here, we will at long last be able to solve the key mysteries that have puzzled scientists for over 50 years: how the corona is heated and how the so. . .
Date: 12/2016 Publisher: Space Science Reviews Pages: 1 - 6 DOI: 10.1007/s11214-016-0323-7 Available at: http://link.springer.com/10.1007/s11214-016-0323-7http://link.springer.com/content/pdf/10.1007/s11214-016-0323-7.pdfhttp://link.springer.com/content/pdf/10.1007/s11214-016-0323-7.pdfhttp://link.springer.com/article/10.1007/s11214-016-0323-7/fulltext.html
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Authors: Brodu E., and Balat-Pichelin M.
Title: Emissivity of Boron Nitride and Metals for the Solar Probe Plus Mission
Abstract:
For application to the Solar Probe Plus mission (NASA), the behavior and the thermo-optical performance at very high temperatures (range 1100–2200 K) of candidate passive thermal control materials was assessed. On one hand, a pyrolytic boron nitride coating (130  μm 130  μm thick) was proved to be stable at high temperatures up to 2200 K in vacuum, as well as proved, via total and spectral emissivity measurements at high temperatures, to be able to effectively turn an initially selective solar absorber substrate (carbon/carbon composite) into a solar reflector. On the other hand, chemical vapor deposition coatings made of refractory metals with highly textured surfaces were proved to be able to significantly reduce the temperature of a metall. . .
Date: 11/2016 Publisher: Journal of Spacecraft and Rockets Pages: 1119 - 1127 DOI: 10.2514/1.A33453 Available at: https://arc.aiaa.org/doi/10.2514/1.A33453https://arc.aiaa.org/doi/pdf/10.2514/1.A33453
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Authors: Matthaeus H., Weygand M., and Dasso S.
Title: Ensemble Space-Time Correlation of Plasma Turbulence in the Solar Wind
Abstract:

Single point measurement turbulence cannot distinguish variations in space and time. We employ an ensemble of one- and two-point measurements in the solar wind to estimate the space-time correlation function in the comoving plasma frame. The method is illustrated using near Earth spacecraft observations, employing ACE, Geotail, IMP-8, and Wind data sets. New results include an evaluation of both correlation time and correlation length from a single method, and a new assessment of the accuracy of the familiar frozen-in flow approximation. This novel view of the space-time structure of turbulence may prove essential in exploratory space missions such as Solar Probe Plus and Solar Orbiter for which the frozen-in flow hypothesis may not be a useful approximation.


Date: 06/2016 Publisher: Physical Review Letters DOI: 10.1103/PhysRevLett.116.245101 Available at: https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.116.245101
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Authors: Klein Kristopher G., and Chandran Benjamin D. G.
Title: EVOLUTION OF THE PROTON VELOCITY DISTRIBUTION DUE TO STOCHASTIC HEATING IN THE NEAR-SUN SOLAR WIND
Abstract:

We investigate how the proton distribution function evolves when the protons undergo stochastic heating by strong, low-frequency, Alfvén-wave turbulence under the assumption that β is small. We apply our analysis to protons undergoing stochastic heating in the supersonic fast solar wind and obtain proton distributions at heliocentric distances ranging from 4 to 30 solar radii. We find that the proton distribution develops non-Gaussian structure with a flat core and steep tail. For r\gt 5 {R}{{S}}, the proton distribution is well approximated by a modified Moyal distribution. Comparisons with future measurements from Solar Probe Plus could be used to test whether stochastic heating is occurring in the solar-wind acceleration region.


Date: 03/2016 Publisher: The Astrophysical Journal Pages: 47 DOI: 10.3847/0004-637X/820/1/47 Available at: http://stacks.iop.org/0004-637X/820/i=1/a=47?key=crossref.3bba6a0e184137847bf77cde72a2fe1fhttp://stacks.iop.org/0004-637X/820/i=1/a=47/pdfhttp://stacks.iop.org/0004-637X/820/i=1/a=47?key=crossref.3bba6a0e184137847bf77cde72a2fe1f
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Authors: Bale S. D., Goetz K., Harvey P. R., Turin P., Bonnell J. W., et al.
Title: The FIELDS Instrument Suite for Solar Probe Plus
Abstract:

NASA's Solar Probe Plus (SPP) mission will make the first in situ measurements of the solar corona and the birthplace of the solar wind. The FIELDS instrument suite on SPP will make direct measurements of electric and magnetic fields, the properties of in situ plasma waves, electron density and temperature profiles, and interplanetary radio emissions, amongst other things. Here, we describe the scientific objectives targeted by the SPP/FIELDS instrument, the instrument design itself, and the instrument concept of operations and planned data products.


Date: 12/2016 Publisher: Space Science Reviews Pages: 49 - 82 DOI: 10.1007/s11214-016-0244-5 Available at: http://link.springer.com/10.1007/s11214-016-0244-5http://link.springer.com/content/pdf/10.1007/s11214-016-0244-5.pd
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Authors: Klein K. G., and Howes G. G.
Title: MEASURING COLLISIONLESS DAMPING IN HELIOSPHERIC PLASMAS USING FIELD–PARTICLE CORRELATIONS
Abstract:

An innovative field-particle correlation technique is proposed that uses single-point measurements of the electromagnetic fields and particle velocity distribution functions to investigate the net transfer of energy from fields to particles associated with the collisionless damping of turbulent fluctuations in weakly collisional plasmas, such as the solar wind. In addition to providing a direct estimate of the local rate of energy transfer between fields and particles, it provides vital new information about the distribution of that energy transfer in velocity space. This velocity-space signature can potentially be used to identify the dominant collisionless mechanism responsible for the damping of turbulent fluctuations in the solar wind. The application of this novel field-particle co. . .
Date: 08/2016 Publisher: The Astrophysical Journal Pages: L30 DOI: 10.3847/2041-8205/826/2/L30 Available at: http://stacks.iop.org/2041-8205/826/i=2/a=L30?key=crossref.1f33350dac6f20e78faa0a9e9d852985http://stacks.iop.org/2041-8205/826/i=2/a=L30/pdfhttp://stacks.iop.org/2041-8205/826/i=2/a=L30?key=crossref.1f33350dac6f20e78faa0a9e9d852985
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Authors: Clemens Adam, and Burgess David
Title: Pickup ion processes associated with spacecraft thrusters: Implications for solar probe plus
Abstract:

Chemical thrusters are widely used in spacecraft for attitude control and orbital manoeuvres. They create an exhaust plume of neutral gas which produces ions via photoionization and charge exchange. Measurements of local plasma properties will be affected by perturbations caused by the coupling between the newborn ions and the plasma. A model of neutral expansion has been used in conjunction with a fully three-dimensional hybrid code to study the evolution and ionization over time of the neutral cloud produced by the firing of a mono-propellant hydrazine thruster as well as the interactions of the resulting ion cloud with the ambient solar wind. Results are presented which show that the plasma in the region near to the spacecraft will be perturbed for an extended period of time with the. . .
Date: 03/2016 Publisher: Physics of Plasmas Pages: 032901 DOI: 10.1063/1.4942938 Available at: http://aip.scitation.org/doi/10.1063/1.4942938http://aip.scitation.org/doi/pdf/10.1063/1.4942938
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Authors: Cranmer Steven R.
Title: Predictions for Dusty Mass Loss from Asteroids During Close Encounters with Solar Probe Plus
Abstract:

The Solar Probe Plus ( SPP) mission will explore the Sun's corona and innermost solar wind starting in 2018. The spacecraft will also come close to a number of Mercury-crossing asteroids with perihelia less than 0.3 AU. At small heliocentric distances, these objects may begin to lose mass, thus becoming "active asteroids" with comet-like comae or tails. This paper assembles a database of 97 known Mercury-crossing asteroids that may be encountered by SPP, and it presents estimates of their time-dependent visible-light fluxes and mass loss rates. Assuming a similar efficiency of sky background subtraction as was achieved by STEREO , we find that approximately 80 % of these asteroids are bright enough to be observed by the Wide-field Imager for SPP (WISPR). A model of gas/dust mass loss fr. . .
Date: 11/2016 Publisher: Earth, Moon, and Planets Pages: 51 - 79 DOI: 10.1007/s11038-016-9490-5 Available at: http://link.springer.com/10.1007/s11038-016-9490-5http://link.springer.com/content/pdf/10.1007/s11038-016-9490-5.pdfhttp://link.springer.com/content/pdf/10.1007/s11038-016-9490-5.pdfhttp://link.springer.com/article/10.1007/s11038-016-9490-5/fulltext.html
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Authors: Abbo L., Ofman L., Antiochos S. K., Hansteen V. H., Harra L., et al.
Title: Slow Solar Wind: Observations and Modeling
Abstract:

While it is certain that the fast solar wind originates from coronal holes, where and how the slow solar wind (SSW) is formed remains an outstanding question in solar physics even in the post-SOHO era. The quest for the SSW origin forms a major objective for the planned future missions such as the Solar Orbiter and Solar Probe Plus. Nonetheless, results from spacecraft data, combined with theoretical modeling, have helped to investigate many aspects of the SSW. Fundamental physical properties of the coronal plasma have been derived from spectroscopic and imaging remote-sensing data and in situ data, and these results have provided crucial insights for a deeper understanding of the origin and acceleration of the SSW. Advanced models of the SSW in coronal streamers and other structures ha. . .
Date: 11/2016 Publisher: Space Science Reviews Pages: 55 - 108 DOI: 10.1007/s11214-016-0264-1 Available at: http://link.springer.com/10.1007/s11214-016-0264-1http://link.springer.com/content/pdf/10.1007/s11214-016-0264-1.pdfhttp://link.springer.com/content/pdf/10.1007/s11214-016-0264-1.pdfhttp://link.springer.com/article/10.1007/s11214-016-0264-1/fulltext.html
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Authors: Schwadron N. A., Bastian T., Leibacher J., Gary D., Pevtsov A., et al.
Title: The Solar Probe Plus Ground Based Network
Abstract:

Executive Summary. The role of the Solar Probe Plus (SPP) Ground-Based Network

(SPP-GBN) is to optimize and enhance the science return of the SPP mission by

providing unique data from the ground. The role of the GBN extends to planning and

coordination, supported by appropriate infrastructure, to ensure that the right kinds of

observations are acquired by the various facilities (see below), at the right times, and that

the data are readily accessible to the community for a variety of uses. The SPP-GBN

addresses science questions that will help interpreting SPP data, but also provide global

context and allow us to understand how SPP observations inform our understanding of

solar phenomena. Specifically, the S. . .
Date: DOI: N/A Available at: http://sppgway.jhuapl.edu/sites/default/files/Pubs/SPP-GBN-WhitePaper-v5.0.pdf
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Authors: Fox N. J., Velli M. C., Bale S. D., Decker R., Driesman A., et al.
Title: The Solar Probe Plus Mission: Humanity’s First Visit to Our Star
Abstract:

Solar Probe Plus (SPP) will be the first spacecraft to fly into the low solar corona. SPP's main science goal is to determine the structure and dynamics of the Sun's coronal magnetic field, understand how the solar corona and wind are heated and accelerated, and determine what processes accelerate energetic particles. Understanding these fundamental phenomena has been a top-priority science goal for over five decades, dating back to the 1958 Simpson Committee Report. The scale and concept of such a mission has been revised at intervals since that time, yet the core has always been a close encounter with the Sun. The mission design and the technology and engineering developments enable SPP to meet its science objectives to: (1) Trace the flow of energy that heats and accelerates the sola. . .
Date: 12/2016 Publisher: Space Science Reviews Pages: 7 - 48 DOI: 10.1007/s11214-015-0211-6 Available at: http://link.springer.com/10.1007/s11214-015-0211-6http://link.springer.com/content/pdf/10.1007/s11214-015-0211-6.pdf
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Authors: Chhiber R, Usmanov AV, Matthaeus WH, and Goldstein ML
Title: SOLAR WIND COLLISIONAL AGE FROM A GLOBAL MAGNETOHYDRODYNAMICS SIMULATION
Abstract:

Simple estimates of the number of Coulomb collisions experienced by the interplanetary plasma to the point of observation, I.e., the “collisional age”, can be usefully employed in the study of non-thermal features of the solar wind. Usually these estimates are based on local plasma properties at the point of observation. Here we improve the method of estimation of the collisional age by employing solutions obtained from global three-dimensional magnetohydrodynamics simulations. This enables evaluation of the complete analytical expression for the collisional age without using approximations. The improved estimation of the collisional timescale is compared with turbulence and expansion timescales to assess the relative importance of collisions. The collisional age computed using the . . .
Date: 04/2016 Publisher: The Astrophysical Journal Pages: 34 DOI: 10.3847/0004-637X/821/1/34 Available at: http://stacks.iop.org/0004-637X/821/i=1/a=34?key=crossref.788f196bae255efe123dabca17bb586dhttp://stacks.iop.org/0004-637X/821/i=1/a=34/pdfhttp://stacks.iop.org/0004-637X/821/i=1/a=34?key=crossref.788f196bae255efe123dabca17bb586d
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Authors: Vourlidas Angelos, Howard Russell A., Plunkett Simon P., Korendyke Clarence M., Thernisien Arnaud F. R., et al.
Title: The Wide-Field Imager for Solar Probe Plus (WISPR)
Abstract: N/A
Date: 02/2015 Publisher: Space Science Reviews Pages: 83 - 130 DOI: 10.1007/s11214-014-0114-y Available at: http://link.springer.com/content/pdf/10.1007/s11214-014-0114-y.pdf
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2015
Authors: de Patoul Judith, Foullon Claire, and Riley Pete
Title: 3D ELECTRON DENSITY DISTRIBUTIONS IN THE SOLAR CORONA DURING SOLAR MINIMA: ASSESSMENT FOR MORE REALISTIC SOLAR WIND MODELING
Abstract:

Knowledge of the electron density distribution in the solar corona put constraints on the magnetic field configurations for coronal modeling and on initial conditions for solar wind modeling. We work with polarized SOHO/LASCO-C2 images from the last two recent minima of solar activity (1996-1997 and 2008-2010), devoid of coronal mass ejections. The goals are to derive the 4D electron density distributions in the corona by applying a newly developed time-dependent tomographic reconstruction method and to compare the results between the two solar minima and with two magnetohydrodynamic models. First, we confirm that the values of the density distribution in thermodynamic models are more realistic than in polytropic ones. The tomography provides more accurate distributions in the polar reg. . .
Date: 11/2015 Publisher: The Astrophysical Journal Pages: 68 DOI: 10.1088/0004-637X/814/1/68 Available at: http://stacks.iop.org/0004-637X/814/i=1/a=68?key=crossref.845557cfda4b2a3786588c8b62dbb093
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Authors: Daloz Anne S., Camargo S. J., Kossin J. P., Emanuel K., Horn M., et al.
Title: Cluster Analysis of Downscaled and Explicitly Simulated North Atlantic Tropical Cyclone Tracks
Abstract:

A realistic representation of the North Atlantic tropical cyclone tracks is crucial as it allows, for example, explaining potential changes in U.S. landfalling systems. Here, the authors present a tentative study that examines the ability of recent climate models to represent North Atlantic tropical cyclone tracks. Tracks from two types of climate models are evaluated: explicit tracks are obtained from tropical cyclones simulated in regional or global climate models with moderate to high horizontal resolution (1°–0.25°), and downscaled tracks are obtained using a downscaling technique with large-scale environmental fields from a subset of these models. For both configurations, tracks are objectively separated into four groups using a cluster technique, leading to a zonal and a merid. . .
Date: 02/2015 Publisher: Journal of Climate Pages: 1333 - 1361 DOI: 10.1175/JCLI-D-13-00646.1 Available at: http://journals.ametsoc.org/doi/10.1175/JCLI-D-13-00646.1
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Authors: el H. ̧, Motschmann U., üchner J., Narita Y., and Nariyuki Y.
Title: ION-SCALE TURBULENCE IN THE INNER HELIOSPHERE: RADIAL DEPENDENCE
Abstract:

The evolution of the ion-scale plasma turbulence in the inner heliosphere is studied by associating the plasma parameters for hybrid-code turbulence simulations to the radial distance from the Sun via a Solar wind model based mapping procedure. Using a mapping based on a one-dimensional solar wind expansion model, the resulting ion-kinetic scale turbulence is related to the solar wind distance from the Sun. For this purpose the mapping is carried out for various values of ion beta that correspond to the heliocentric distance. It is shown that the relevant normal modes such as ion cyclotron and ion Bernstein modes will occur first at radial distances of about 0.2-0.3 AU, i.e., near the Mercury orbit. This finding can be used as a reference, a prediction to guide the in situ measurements . . .
Date: 10/2015 Publisher: The Astrophysical Journal Pages: 175 DOI: 10.1088/0004-637X/812/2/175 Available at: http://stacks.iop.org/0004-637X/812/i=2/a=175?key=crossref.a9d511ae127248e735f11254de6e3bb9
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Authors: Isenberg Philip A., and Vasquez Bernard J.
Title: KINETIC EVOLUTION OF CORONAL HOLE PROTONS BY IMBALANCED ION-CYCLOTRON WAVES: IMPLICATIONS FOR MEASUREMENTS BY SOLAR PROBE PLUS
Abstract:

We extend the kinetic guiding-center model of collisionless coronal hole protons presented in Isenberg & Vasquez to consider driving by imbalanced spectra of obliquely propagating ion-cyclotron waves. These waves are assumed to be a small by-product of the imbalanced turbulent cascade to high perpendicular wavenumber, and their total intensity is taken to be 1% of the total fluctuation energy. We also extend the kinetic solutions for the proton distribution function in the resulting fast solar wind to heliocentric distances of 20 solar radii, which will be attainable by the Solar Probe Plus spacecraft. We consider three ratios of outward-propagating to inward-propagating resonant intensities: 1, 4, and 9. The self-consistent bulk flow speed reaches fast solar wind values in all case. . .
Date: 08/2015 Publisher: The Astrophysical Journal Pages: 119 DOI: 10.1088/0004-637X/808/2/119 Available at: http://stacks.iop.org/0004-637X/808/i=2/a=119?key=crossref.961efccaa84816c8b4c9e041f523e07f
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Authors: Klein Kristopher G., Perez Jean C., Verscharen Daniel, Mallet Alfred, and Chandran Benjamin D. G.
Title: A MODIFIED VERSION OF TAYLOR’S HYPOTHESIS FOR SOLAR PROBE PLUS OBSERVATIONS
Abstract:

The Solar Probe Plus (SPP) spacecraft will explore the near-Sun environment, reaching heliocentric distances less than 10 {{R}}. Near Earth, spacecraft measurements of fluctuating velocities and magnetic fields taken in the time domain are translated into information about the spatial structure of the solar wind via Taylor’s “frozen turbulence” hypothesis. Near the perihelion of SPP, however, the solar-wind speed is comparable to the Alfvén speed, and Taylor’s hypothesis in its usual form does not apply. In this paper, we show that under certain assumptions, a modified version of Taylor’s hypothesis can be recovered in the near-Sun region. We consider only the transverse, non-compressive component of the fluctuations at length scales exceeding the proton gyrora. . .
Date: 03/2015 Publisher: The Astrophysical Journal Pages: L18 DOI: 10.1088/2041-8205/801/1/L18 Available at: http://stacks.iop.org/2041-8205/801/i=1/a=L18?key=crossref.c92a2bde23ce9cdd58185dec581d5a09
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Authors: Plus M., Auby I., Maurer D., Trut G., Del Amo Y., et al.
Title: Phytoplankton versus macrophyte contribution to primary production and biogeochemical cycles of a coastal mesotidal system. A modelling approach
Abstract:

This study presents an assessment of the contributions of various primary producers to the global annual production and N/P cycles of a coastal system, namely the Arcachon Bay, by means of a numerical model. This 3D model fully couples hydrodynamic with ecological processes and simulates nitrogen, silicon and phosphorus cycles as well as phytoplankton, macroalgae and seagrasses. Total annual production rates for the different components were calculated for different years (2005, 2007 and 2009) during a time period of drastic reduction in seagrass beds since 2005. The total demand of nitrogen and phosphorus was also calculated and discussed with regards to the riverine inputs. Moreover, this study presents the first estimation of particulate organic carbon export to the adjacent open oce. . .
Date: 11/2015 Publisher: Estuarine, Coastal and Shelf Science Pages: 52 - 60 DOI: 10.1016/j.ecss.2015.09.003 Available at: https://linkinghub.elsevier.com/retrieve/pii/S0272771415300810https://api.elsevier.com/content/article/PII:S0272771415300810?httpAccept=text/xmlhttps://api.elsevier.com/content/article/PII:S0272771415300810?httpAccept=text/plain
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