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20 results on '"Le Contel, O."'

1. Direct observations of energy transfer from resonant electrons to whistler-mode waves in magnetosheath of Earth

Author

Kitamura, N., Amano, T., Omura, Y., Boardsen, S. A., Gershman, D. J., Miyoshi, Y., Kitahara, M., Katoh, Y., Kojima, H., Nakamura, S., Shoji, M., Saito, Y., Yokota, S., Giles, B. L., Paterson, W. R., Pollock, C. J., Barrie, A. C., Skeberdis, D. G., Kreisler, S., Le Contel, O., Russell, C. T., Strangeway, R. J., Lindqvist, P.-A., Ergun, R. E., Torbert, R. B., and Burch, J. L.

Published
2022
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3. Global Compression of the Plasma Sheet and Magnetotail During Intense Storms From THEMIS Observations.

Author

Alqeeq, S. W., Fontaine, D., Le Contel, O., Akhavan Tafti, M., Cazzola, E., Atilaw, T., Angelopoulos, V., and Auster, H. U.

Subjects
CORONAL mass ejections, STORMS, SPACE environment, MAGNETIC storms, DYNAMIC pressure, SOLAR wind
Abstract

We estimate the global impact of storms on the global structure and dynamics of the night side plasma sheet from observations by the NASA mission Time History of Events and Macroscale Interactions during Substorms (THEMIS). We focus on an intense storm occurring in December 2015 triggered by interplanetary coronal mass ejections (ICMEs). It starts with a storm sudden commencement (SSC) phase (SYM‐H ∼ ${\sim} $ +50 nT) followed by a growth phase (SYM‐H ∼ ${\sim} $ −188 nT at the minimum) and then a long recovery phase lasting several days. We investigate THEMIS observations when the spacecraft were located in the midnight sector of the plasma sheet at distances typically between 8 and 13 Earth's radii. It is found that the plasma sheet has been globally compressed up to a value of about ∼> ${\sim} > $4 nPa during the SSC and main phases, that is, 8 times larger than its value during the quiet phase before the event. This compression occurs during periods of high dynamic pressure in the ICME (20 nPa) about one order of magnitude larger than its value in the pristine solar wind. We infer a global increase of the lobe magnetic field from 30 to 100 nT, confirmed by THEMIS data just outside the plasma sheet. During the SSC and main phases, the plasma sheet is found thinner by a factor of 2 relative to its thickness at quiet times, while the Tsyganenko T96 magnetic field model shows very stretched magnetic field lines from inner magnetospheric regions toward the night side. During the recovery phase, whereas the interplanetary pressure has dropped off, the plasma sheet tends to gradually recover its quiet phase characteristics (pressure, thickness, magnetic configuration, etc.) during a long recovery phase of several days. Key Points: The global plasma sheet's structure and dynamics are quantified during storms triggered by interplanetary coronal mass ejections using Time History of Events and Macroscale Interactions during Substorms observationsDuring the storm sudden commencement (SSC) and main phases, the magnetotail and plasma sheet have been compressed by a factor of 8 relative to the preceding quiet phaseUsing the T96 model, the plasma sheet is highly stretched during the storm SSC and main phases, gradually returning to the quiet phase [ABSTRACT FROM AUTHOR]

Published
2024
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5. Reconnection Inside a Dipolarization Front of a Diverging Earthward Fast Flow

Author

Hosner, M., primary, Nakamura, R., additional, Schmid, D., additional, Nakamura, T. K. M., additional, Panov, E. V., additional, Volwerk, M., additional, Vörös, Z., additional, Roberts, O. W., additional, Blasl, K. A., additional, Settino, A., additional, Korovinskiy, D., additional, Marshall, A. T., additional, Denton, R. E., additional, Burch, J. L., additional, Giles, B. L., additional, Torbert, R. B., additional, Le Contel, O., additional, Escoubet, C. P., additional, Dandouras, I. S., additional, Carr, C., additional, and Fazakerley, A. N., additional

Published
2024
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6. Magnetospheric Time‐History in Storm‐Time Magnetic Flux Dynamics: A Global Simulation Campaign.

Author

Atilaw, T. Y., Akhavan‐Tafti, M., Al Shidi, Q., Pulkkinen, T. I., Fontaine, D., Le Contel, O., Slavin, J. A., Le, G., Chen, L.‐J., Reiff, P. H., and Alqeeq, S. W.

Subjects
MAGNETIC flux, MAGNETIC flux density, SOLAR photosphere, STORMS, SPACE environment
Abstract

This paper aims to quantify the magnetospheric magnetic flux contents under moderate to intense space weather conditions using global simulations. This study is a companion to Akhavan‐Tafti, Atilaw, et al. (2023, https://doi.org/10.1029/2023JA031832) where magnetic flux evolution is presented for a catalog of storm events, using Heliophysics System Observatory (HSO) observations. For this study, we used the Space Weather Modeling Framework (SWMF) in Geospace configuration to study magnetic flux dynamics for a subset of their storm events (15 events). Simulations reliably resolve the storm‐time magnetic flux Bz and current density |J| asymmetries across the different storm phases. It is revealed that: relative to the quiet period, flux content is enhanced during the storm sudden commencement (SSC) phase in the dayside by ΔBz/Bz, quiet = +17%, and reduced in the nightside magnetosphere (r[RE] < −6 RE) by −15%. At the same time, the cross‐tail current is found to enhance (|J| = 2 nA/m2), which suggests the storm impact in the nightside magnetosphere is much earlier in the storm cycle than previously shown. Concurring with previous studies, a significant depletion of magnetic flux by up to −40%, with day‐night and dawn‐dusk asymmetries, can be seen during the main and recovery phases. This corresponds to the enhanced current density (|J| = 5–8 nA/m2) at ∼6 RE further confirming the role of ring current in driving magnetospheric dynamics during the main and recovery phases. This is in contrast with the SSC phase wherein the Chapman‐Ferraro and cross‐tail currents are the dominant current systems. Key Points: The nightside magnetospheric flux is impacted by the storm event earlier in the storm cycle than expected, (i.e., the SSC phase)Decrease in flux content of up to −40% within the inner magnetosphere for the main and recovery phases is associated with the enhanced ring currentStorm‐time asymmetries in magnetic flux and current density are well‐resolved throughout the storm phases [ABSTRACT FROM AUTHOR]

Published
2024
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7. Two Classes of Equatorial Magnetotail Dipolarization Fronts Observed by Magnetospheric Multiscale Mission: A Statistical Overview

Author

Alqeeq, S. W., primary, Le Contel, O., additional, Canu, P., additional, Retinò, A., additional, Chust, T., additional, Mirioni, L., additional, Chuvatin, A., additional, Nakamura, R., additional, Ahmadi, N., additional, Wilder, F. D., additional, Gershman, D. J., additional, Khotyaintsev, Yu. V., additional, Lindqvist, P.‐A., additional, Ergun, R. E., additional, Burch, J. L., additional, Torbert, R. B., additional, Fuselier, S. A., additional, Russell, C. T., additional, Wei, H. Y., additional, Strangeway, R. J., additional, Bromund, K. R., additional, Fischer, D., additional, Giles, B. L., additional, and Saito, Y., additional

Published
2023
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8. Magnetospheric Time History in Storm‐Time Magnetic Flux Dynamics.

Author

Akhavan‐Tafti, M., Atilaw, T. Y., Fontaine, D., Le Contel, O., Slavin, J. A., and Pulkkinen, T.

Subjects
MAGNETIC flux, EXTREME weather, CORONAL mass ejections, WEATHER forecasting, SPACE environment
Abstract

Magnetospheric magnetic flux dynamics is quantified in 29 geomagnetic storms between 2015 and 2019, using near‐equatorial Van Allen Probe, GOES, and Magnetospheric Multiscale satellites. For the first time, concurrent, multi‐probe observations are utilized to preserve magnetospheric time history, defined as the state of the magnetosphere leading up to an observation. It is revealed that, relative to pre‐storm conditions, (a) during the storm sudden commencement (SSC), magnetic flux uniformly increases ΔΨ = +15% throughout the magnetosphere, except in the nightside inner magnetosphere where ΔΨ = −30%, and (b) during storm main and recovery phases, ΔΨ = −30% and −15%, respectively, in the nightside magnetosphere, at radial distances 5 ≤ r [RE] < 8. It is found that a symmetric ring current is likely formed in the nightside, early in the storm process (localized during SSC), which then broadens during the main phase, before weakening during the recovery phase. The current system on the dayside shows a distinct dawn‐dusk asymmetry. Plain Language Summary: The Earth's magnetosphere serves as a shield against extreme space weather conditions, including interplanetary coronal mass ejections. Understanding the magnetospheric dynamics during geomagnetic storms is critical for a reliable and accurate space weather prediction capability. This study provides a novel statistical analysis technique for investigating the magnetospheric closed magnetic flux content during different storm phases, using magnetic field data from a multitude of satellite missions. The technique considers critical information, such as the state of the magnetosphere before a geomagnetic storm. This multi‐mission analysis technique, though challenging due to orbital differences, provides a comprehensive view of the storm‐time magnetosphere. Our analysis suggests that the magnetosphere is non‐uniformly impacted by different geomagnetic storm phases, paving the path for more reliable storm prediction models. Key Points: Concurrent, multi‐probe observations help preserve magnetospheric time history for a more reliable space weather prediction capabilityMagnetic flux is substantially reduced in the nightside inner magnetosphere during all storm phases, relative to the quiet periodMagnetic flux changes between different storm phases are most significant in the nightside inner magnetosphere, asymmetric on the dayside [ABSTRACT FROM AUTHOR]

Published
2023
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10. Evidence for Whistler Waves Propagating Into the Electron Diffusion Region of Collisionless Magnetic Reconnection

Author

Zhong, Z. H., Zhou, M., Graham, Daniel B., Khotyaintsev, Yuri V., Wu, Y. F., Le Contel, O., Li, H. M., Tao, X., Tang, R. X., Deng, X. H., Zhong, Z. H., Zhou, M., Graham, Daniel B., Khotyaintsev, Yuri V., Wu, Y. F., Le Contel, O., Li, H. M., Tao, X., Tang, R. X., and Deng, X. H.

Abstract

Despite a growing number of observations of whistler waves in/around the reconnection diffusion region, the origin of the whistler waves in the diffusion region and their role in reconnection remain elusive. This paper investigates the whistler-mode waves within an electron-scale reconnecting current sheet observed by the Magnetospheric Multiscale mission on 23 December 2016. These whistlers were observed in both the electron diffusion region (EDR) and the immediate inflow region of the electron-scale magnetic reconnection site. The dispersion relation of these whistlers is measured and compared to predictions from linear theory for the first time in these regions. The comparison shows that the field-aligned drifting electron component critically modifies the dispersion relation of whistlers in the EDR due to the Doppler-shift effects. We demonstrate that these whistlers propagated into the EDR from outside rather than locally excited, however, they did not provide sufficiently large anomalous dissipation in this EDR.

Published
2022
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11. Investigation of the homogeneity of energy conversion processes at dipolarization fronts from MMS measurements

Author

Alqeeq, S. W., Le Contel, O., Canu, P., Retino, A., Chust, T., Mirioni, L., Richard, Louis, Ait-Si-Ahmed, Y., Alexandrova, A., Chuvatin, A., Ahmadi, N., Baraka, S. M., Nakamura, R., Wilder, F. D., Gershman, D. J., Lindqvist, P. A., Khotyaintsev, Yuri V., Ergun, R. E., Burch, J. L., Torbert, R. B., Russell, C. T., Magnes, W., Strangeway, R. J., Bromund, K. R., Wei, H., Plaschke, F., Anderson, B. J., Giles, B. L., Fuselier, S. A., Saito, Y., Lavraud, B., Alqeeq, S. W., Le Contel, O., Canu, P., Retino, A., Chust, T., Mirioni, L., Richard, Louis, Ait-Si-Ahmed, Y., Alexandrova, A., Chuvatin, A., Ahmadi, N., Baraka, S. M., Nakamura, R., Wilder, F. D., Gershman, D. J., Lindqvist, P. A., Khotyaintsev, Yuri V., Ergun, R. E., Burch, J. L., Torbert, R. B., Russell, C. T., Magnes, W., Strangeway, R. J., Bromund, K. R., Wei, H., Plaschke, F., Anderson, B. J., Giles, B. L., Fuselier, S. A., Saito, Y., and Lavraud, B.

Abstract

We report on six dipolarization fronts (DFs) embedded in fast earthward flows detected by the Magnetospheric Multiscale mission during a substorm event on 23 July 2017. We analyzed Ohm's law for each event and found that ions are mostly decoupled from the magnetic field by Hall fields. However, the electron pressure gradient term is also contributing to the ion decoupling and likely responsible for an electron decoupling at DF. We also analyzed the energy conversion process and found that the energy in the spacecraft frame is transferred from the electromagnetic field to the plasma (J & BULL; E > 0) ahead or at the DF, whereas it is the opposite (J & BULL; E < 0) behind the front. This reversal is mainly due to a local reversal of the cross-tail current indicating a substructure of the DF. In the fluid frame, we found that the energy is mostly transferred from the plasma to the electromagnetic field (J & BULL; E & PRIME; < 0) and should contribute to the deceleration of the fast flow. However, we show that the energy conversion process is not homogeneous at the electron scales due to electric field fluctuations likely related to lower-hybrid drift waves. Our results suggest that the role of DF in the global energy cycle of the magnetosphere still deserves more investigation. In particular, statistical studies on DF are required to be carried out with caution due to these electron scale substructures.

Published
2022
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13. Investigation of the homogeneity of energy conversion processes at dipolarization fronts from MMS measurements

Author

Alqeeq, S. W., primary, Le Contel, O., additional, Canu, P., additional, Retinò, A., additional, Chust, T., additional, Mirioni, L., additional, Richard, L., additional, Aït-Si-Ahmed, Y., additional, Alexandrova, A., additional, Chuvatin, A., additional, Ahmadi, N., additional, Baraka, S. M., additional, Nakamura, R., additional, Wilder, F. D., additional, Gershman, D. J., additional, Lindqvist, P. A., additional, Khotyaintsev, Yu. V., additional, Ergun, R. E., additional, Burch, J. L., additional, Torbert, R. B., additional, Russell, C. T., additional, Magnes, W., additional, Strangeway, R. J., additional, Bromund, K. R., additional, Wei, H., additional, Plaschke, F., additional, Anderson, B. J., additional, Giles, B. L., additional, Fuselier, S. A., additional, Saito, Y., additional, and Lavraud, B., additional

Published
2022
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15. Low-frequency Whistler Waves Modulate Electrons and Generate Higher-frequency Whistler Waves in the Solar Wind

Author

Yao, S. T., primary, Shi, Q. Q., additional, Zong, Q. G., additional, Degeling, A. W., additional, Guo, R. L., additional, Li, L., additional, Li, J. X., additional, Tian, A. M., additional, Zhang, H., additional, Yao, Z. H., additional, Fu, H. S., additional, Liu, C. M., additional, Sun, W. J., additional, Niu, Z., additional, Li, W. Y., additional, Liu, Z. Y., additional, Le Contel, O., additional, Zhang, S., additional, Xiao, C., additional, Shang, W. S., additional, Torbert, R. B., additional, Ergun, R. E., additional, Lindqvist, P.-A., additional, and Pollock, C. J., additional

Published
2021
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16. Whistler waves observed by Solar Orbiter/RPW between 0.5 AU and 1 AU

Author

Kretzschmar, M., primary, Chust, T., additional, Krasnoselskikh, V., additional, Graham, D., additional, Colomban, L., additional, Maksimovic, M., additional, Khotyaintsev, Yu. V., additional, Soucek, J., additional, Steinvall, K., additional, Santolík, O., additional, Jannet, G., additional, Brochot, J.-Y., additional, Le Contel, O., additional, Vecchio, A., additional, Bonnin, X., additional, Bale, S. D., additional, Froment, C., additional, Larosa, A., additional, Bergerard-Timofeeva, M., additional, Fergeau, P., additional, Lorfevre, E., additional, Plettemeier, D., additional, Steller, M., additional, Štverák, Š., additional, Trávníček, P., additional, Vaivads, A., additional, Horbury, T. S., additional, O’Brien, H., additional, Evans, V., additional, Angelini, V., additional, Owen, C. J., additional, and Louarn, P., additional

Published
2021
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17. Observations of whistler mode waves by Solar Orbiter’s RPW Low Frequency Receiver (LFR): In-flight performance and first results

Author

Chust, T., primary, Kretzschmar, M., additional, Graham, D. B., additional, Le Contel, O., additional, Retinò, A., additional, Alexandrova, A., additional, Berthomier, M., additional, Hadid, L. Z., additional, Sahraoui, F., additional, Jeandet, A., additional, Leroy, P., additional, Pellion, J.-C., additional, Bouzid, V., additional, Katra, B., additional, Piberne, R., additional, Khotyaintsev, Yu. V., additional, Vaivads, A., additional, Krasnoselskikh, V., additional, Souček, J., additional, Santolík, O., additional, Lorfèvre, E., additional, Plettemeier, D., additional, Steller, M., additional, Štverák, Š., additional, Trávníček, P., additional, Vecchio, A., additional, Maksimovic, M., additional, Bale, S. D., additional, Horbury, T. S., additional, O’Brien, H., additional, Evans, V., additional, and Angelini, V., additional

Published
2021
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18. First observations and performance of the RPW instrument on board the Solar Orbiter mission

Author

Maksimovic, M., primary, Souček, J., additional, Chust, T., additional, Khotyaintsev, Y., additional, Kretzschmar, M., additional, Bonnin, X., additional, Vecchio, A., additional, Alexandrova, O., additional, Bale, S. D., additional, Bérard, D., additional, Brochot, J.-Y., additional, Edberg, N. J. T., additional, Eriksson, A., additional, Hadid, L. Z., additional, Johansson, E. P. G., additional, Karlsson, T., additional, Katra, B., additional, Krasnoselskikh, V., additional, Krupař, V., additional, Lion, S., additional, Lorfèvre, E., additional, Matteini, L., additional, Nguyen, Q. N., additional, Píša, D., additional, Piberne, R., additional, Plettemeier, D., additional, Rucker, H. O., additional, Santolík, O., additional, Steinvall, K., additional, Steller, M., additional, Štverák, Š., additional, Trávníček, P., additional, Vaivads, A., additional, Zaslavsky, A., additional, Chaintreuil, S., additional, Dekkali, M., additional, Astier, P.-A., additional, Barbary, G., additional, Boughedada, K., additional, Cecconi, B., additional, Chapron, F., additional, Collin, C., additional, Dias, D., additional, Guéguen, L., additional, Lamy, L., additional, Leray, V., additional, Malac-Allain, L. R., additional, Pantellini, F., additional, Parisot, J., additional, Plasson, P., additional, Thijs, S., additional, Fratter, I., additional, Bellouard, E., additional, Danto, P., additional, Julien, S., additional, Guilhem, E., additional, Fiachetti, C., additional, Sanisidro, J., additional, Laffaye, C., additional, Gonzalez, F., additional, Pontet, B., additional, Quéruel, N., additional, Jannet, G., additional, Fergeau, P., additional, Dudok de Wit, T., additional, Vincent, T., additional, Agrapart, C., additional, Pragout, J., additional, Bergerard-Timofeeva, M., additional, Delory, G. T., additional, Turin, P., additional, Jeandet, A., additional, Leroy, P., additional, Pellion, J.-C., additional, Bouzid, V., additional, Recart, W., additional, Kolmašová, I., additional, Krupařová, O., additional, Uhlíř, L., additional, Lán, R., additional, Baše, J., additional, André, M., additional, Bylander, L., additional, Cripps, V., additional, Cully, C., additional, Jansson, S.-E., additional, Puccio, W., additional, Břínek, J., additional, Ottacher, H., additional, Angelini, V., additional, Berthomier, M., additional, Evans, V., additional, Goetz, K., additional, Hellinger, P., additional, Horbury, T. S., additional, Issautier, K., additional, Kontar, E., additional, Le Contel, O., additional, Louarn, P., additional, Martinović, M., additional, Müller, D., additional, O’Brien, H., additional, Owen, C. J., additional, Retino, A., additional, Rodríguez-Pacheco, J., additional, Sahraoui, F., additional, Sanchez, L., additional, Walsh, A. P., additional, Wimmer-Schweingruber, R. F., additional, and Zouganelis, I., additional

Published
2021
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19. Solar Orbiter’s first Venus flyby: Observations from the Radio and Plasma Wave instrument

Author

Hadid, L. Z., primary, Edberg, N. J. T., additional, Chust, T., additional, Píša, D., additional, Dimmock, A. P., additional, Morooka, M. W., additional, Maksimovic, M., additional, Khotyaintsev, Yu. V., additional, Souček, J., additional, Kretzschmar, M., additional, Vecchio, A., additional, Le Contel, O., additional, Retino, A., additional, Allen, R. C., additional, Volwerk, M., additional, Fowler, C. M., additional, Sorriso-Valvo, L., additional, Karlsson, T., additional, Santolík, O., additional, Kolmašová, I., additional, Sahraoui, F., additional, Stergiopoulou, K., additional, Moussas, X., additional, Issautier, K., additional, Dewey, R. M., additional, Klein Wolt, M., additional, Malandraki, O. E., additional, Kontar, E. P., additional, Howes, G. G., additional, Bale, S. D., additional, Horbury, T. S., additional, Martinović, M., additional, Vaivads, A., additional, Krasnoselskikh, V., additional, Lorfèvre, E., additional, Plettemeier, D., additional, Steller, M., additional, Štverák, Š., additional, Trávníček, P., additional, O’Brien, H., additional, Evans, V., additional, Angelini, V., additional, Velli, M. C., additional, and Zouganelis, I., additional

Published
2021
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