Found 5 results
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Filters: Author is Meyer-Vernet, N.  [Clear All Filters]
2020
Authors: Maksimovic M., Bale S. D., Berčič L., Bonnell J. W., Case A. W., et al.
Title: Anticorrelation between the Bulk Speed and the Electron Temperature in the Pristine Solar Wind: First Results from the Parker Solar Probe and Comparison with Helios
Abstract:

We discuss the solar wind electron temperatures Te as measured in the nascent solar wind by Parker Solar Probe during its first perihelion pass. The measurements have been obtained by fitting the high-frequency part of quasi-thermal noise spectra recorded by the Radio Frequency Spectrometer. In addition we compare these measurements with those obtained by the electrostatic analyzer discussed in Halekas et al. These first electron observations show an anticorrelation between Te and the wind bulk speed V: this anticorrelation is most likely the remnant of the well-known mapping observed at 1 au and beyond between the fast wind and its coronal hole sources, where electrons are observed to be cooler than in the quiet corona. We also revisit Helios electron temperature . . .
Date: 02/2020 Publisher: The Astrophysical Journal Supplement Series Pages: 62 DOI: 10.3847/1538-4365/ab61fc Available at: https://iopscience.iop.org/article/10.3847/1538-4365/ab61fch
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2019
Authors: Bale S. D., Badman S. T., Bonnell J. W., Bowen T. A., Burgess D., et al.
Title: Highly structured slow solar wind emerging from an equatorial coronal hole
Abstract:

During the solar minimum, when the Sun is at its least active, the solar wind is observed at high latitudes as a predominantly fast (more than 500 kilometres per second), highly Alfvénic rarefied stream of plasma originating from deep within coronal holes. Closer to the ecliptic plane, the solar wind is interspersed with a more variable slow wind of less than 500 kilometres per second. The precise origins of the slow wind streams are less certain; theories and observations suggest that they may originate at the tips of helmet streamers, from interchange reconnection near coronal hole boundaries, or within coronal holes with highly diverging magnetic fields. The heating mechanism required to drive the solar wind is also unresolved, although candidate mechanisms include Alfvé;n-wave tur. . .
Date: 12/2019 Publisher: Nature Pages: 237 - 242 DOI: 10.1038/s41586-019-1818-7 Available at: http://www.nature.com/articles/s41586-019-1818-7
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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 a. . .
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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2016
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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2010
Authors: Ergun R. E., Malaspina D. M., Bale S. D., McFadden J. P., Larson D. E., et al.
Title: Spacecraft charging and ion wake formation in the near-Sun environment
Abstract:

A three-dimensional, self-consistent code is employed to solve for the static potential structure surrounding a spacecraft in a high photoelectron environment. The numerical solutions show that, under certain conditions, a spacecraft can take on a negative potential in spite of strong photoelectron currents. The negative potential is due to an electrostatic barrier near the surface of the spacecraft that can reflect a large fraction of the photoelectron flux back to the spacecraft. This electrostatic barrier forms if (1) the photoelectron density at the surface of the spacecraft greatly exceeds the ambient plasma density, (2) the spacecraft size is significantly larger than local Debye length of the photoelectrons, and (3) the thermal electron energy is much larger than the characterist. . .
Date: 07/2010 Publisher: Physics of Plasmas Pages: 072903 DOI: 10.1063/1.3457484 Available at: http://aip.scitation.org/doi/10.1063/1.3457484http://aip.scitation.org/doi/pdf/10.1063/1.3457484
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