Publications

2018

Electron-scale dynamics of the diffusion region during symmetric magnetic reconnection in space
- Torbert R.
- Burch J.
- Phan T.
- Hesse M.
- Argall M.
- Shuster J.
- Ergun R.
- Alm L.
- Nakamura R.
- Genestreti K.
- Gershman D.
- Paterson W.
- Turner D.
- Cohen I.
- Giles B.
- Pollock C.
- Wang S.
- Chen L.-J.
- Stawarz J.
- Eastwood J.
- Hwang K.
- Farrugia C.
- Dors I.
- Vaith H.
- Mouikis C.
- Ardakani A.
- Mauk B.
- Fuselier S.
- Russell C.
- Strangeway R.
- Moore T.
- Drake J.
- Shay M.
- Khotyaintsev Yuri
- Lindqvist P.-A.
- Baumjohann W.
- Wilder F.
- Ahmadi N.
- Dorelli J.
- Avanov L.
- Oka M.
- Baker D.
- Fennell J.
- Blake J.
- Jaynes A.
- Le Contel O.
- Petrinec S.
- Lavraud B.
- Saito Y.
Science, American Association for the Advancement of Science (AAAS), 2018, 362 (6421), pp.1391-1395. (10.1126/science.aat2998)
DOI : 10.1126/science.aat2998
Electric field characterization of atmospheric pressure Helium plasma jets through numerical simulations and comparisons with experiments
- Arsénio Nunes Aleixo Viegas Pedro
, 2018. In this PhD thesis numerical simulations based on a 2D fluid model are used to characterize pulsed Helium plasma jets. The model for He plasma jets is developed to describe He jets flowing in N2 and O2 atmospheres and interacting with targets. The discharge dynamics in He jets impacting a grounded metallic target is analyzed with both positive and negative polarities of applied voltage. The temporal and spatial evolutions of electric field associated to the first and rebound ionization fronts are in good qualitative agreement with recent electric field measurements. Then, the plasma-target interaction occurring between a positive discharge and a BSO dielectric target is investigated in detail and results are directly compared with experiments. A good agreement is obtained between simulations and experiments concerning the temporal and spatial profiles of electric field. Maximum values of electric field inside the target of 5 kV.cm−1 are found. The high electric field in the plasma of the order of dozens of kV.cm−1 is severely depleted by the change of permittivity. As a result, the electric field experienced inside the target is almost exclusively originated by the high values of surface charge deposited on the target surface. Finally, the influence of the electric field evolutions on the production of chemically active species close to the targets is evaluated. It is shown that with metallic targets the synergy between the first and rebound fronts increases species production close to the target.
Développement d’un propulseur plasma à résonance cyclotron électronique pour les satellites
- Vialis Théo
, 2018. Ce travail de thèse porte sur le propulseur électrique de type ECR (résonance cyclotron électronique) développé à l’ONERA. Ce propulseur quasi-neutre, qui utilise une tuyère magnétique pour accélérer le plasma, produit une poussée d’environ 1 mN pour des puissances inférieures à 50 W. Dans cette thèse, on se propose de développer et d’optimiser les diagnostics de mesure des performances du propulseur ECR, d’identifier les paramètres expérimentaux pouvant influencer les performances et d’améliorer la compréhension des phénomènes physiques ayant lieu dans le propulseur. Ces objectifs ont pour finalité l’amélioration des performances. Pour répondre à ces objectifs, plusieurs prototypes à aimant permanent ont été développés, et une balance permettant de mesurer directement la poussée a été modifiée pour caractériser le propulseur. Différentes études paramétriques ont été conduites, qui ont montré que les performances dépendaient directement du rapport entre le débit de xénon et la puissance micro-onde injectée. Il a également été observé que la longueur du conducteur externe de la source plasma et la pression ambiante ont une influence significative sur le niveau de performance. Après optimisation de la géométrie, un rendement total supérieur à 12 % a été obtenu. Des mesures séparées de la poussée thermique et magnétique ont permis de montrer que la composante magnétique était la contribution principale de la poussée dans tous les cas testés. Un code PIC 1D-3V a été utilisé pour simuler le comportement du propulseur, et a permis de reproduire le chauffage des électrons par résonance et l’accélération des espèces chargées dans la tuyère. L’ensemble des travaux ont mis en avant le rôle des composantes parallèle et perpendiculaire de la pression électronique.
Four-spacecraft measurements of the shape and dimensionality of magnetic structures in the near-Earth plasma environment
- Coffey V. N.
- Eastwood Jonathan P.
- Ergun R.
- Farrugia C. J.
- Fuselier S. A.
- Genot V. N.
- Grigorenko E. E.
- Hasegawa H.
- Khotyaintsev Y. V.
- Le Contel Olivier
- Marchaudon A.
- Moore T. E.
- Nakamura R.
- Paterson W. R.
- Phan T.
- Rager A. C.
- Russell C. T.
- Saito Y.
- Sauvaud J.-A.
- Schiff C.
- Smith S. E.
- Toledo-Redondo Sergio
- Torbert R. B.
- Wang S.
- Yokota S.
- Fadanelli S.
- Lavraud B.
- Califano F.
- Jacquey C.
- Vernisse Y.
- Kacem I.
- Penou E.
- Gershman D. J.
- Dorelli J. C.
- Pollock C.
- Giles B. L.
- Avanov L. A.
- Burch J. L.
- Chandler Michael O.
, 2018.
Electromagnetic Surface Waves on Hall Current Sheets Associated with Magnetic Reconnection
- Ergun R.
- Ahmadi N.
- Wilder F. D.
- Goodrich K. A.
- Holmes J.
- Torbert R. B.
- Argall M. R.
- Burch J. L.
- Drake J. F.
- Price L.
- Swisdak M.
- Hesse Michael
- Graham D. B.
- Strangeway R. J.
- Giles B. L.
- Lavraud B.
- Le Contel Olivier
- Retinò Alessandro
- Phan T.
- Stawarz J. E.
- Schwartz S. J.
- Eastwood Jonathan P.
- Newman D.
- Lapenta G.
- Hwang K.-J.
- Nakamura R.
- Norgren C.
, 2018.
Optimal Use of Time Lags Between MMS Spacecraft : Application to the Estimation of Wave-Vectors
- Chanteur Gérard
- Le Contel Olivier
- Retinò Alessandro
- Mirioni Laurent
- Turner D. L.
, 2018.
Kinetic Effects of Cold Plasma on Magnetospheric EMIC Waves
- Toledo-Redondo Sergio
- Lavraud B.
- Fuselier S. A.
- Le Contel Olivier
- Moore T. E.
- Giles B. L.
- Lindqvist P. A.
- Russell C. T.
, 2018, pp.SM33C-3584. The Earth's magnetosphere is populated by particles coming from the Earth's ionosphere and the solar wind. The ionospheric component is often composed by cold (below tens of eV) ions, and it has been shown that these cold ions introduce a shorter length-scale into plasma processes like magnetic reconnection, owing to their smaller gyroradius than hot magnetospheric ions. In addition, Electromagnetic Ion Cyclotron (EMIC) waves do occur in the outer magnetosphere, often in association with ionospheric ions, and serve as a coupling mechanism to the ionosphere and inner magnetosphere. Using the MMS fleet, we investigate the dynamics of these waves when cold ions are present, and compare them to cases without the cold ion component. The short separation between spacecraft plus the high time resolution of MMS allows us to resolve the kinetic properties of these waves with unprecedented detail. When cold ions are present, the wave becomes kinetic to the (hot) ring current ions, whereas the cold ions remain largely magnetized. This results into cold ion trapping that produces density enhancements, which in turn may be linked to the generation of whistlers.
The Role of EN in the Reconnection Diffusion Region
- Pritchard K. R.
- Burch J. L.
- Fuselier S. A.
- Webster J. M.
- Genestreti K. J.
- Broll J. M.
- Phan T.
- Giles B. L.
- Torbert R. B.
- Russell C. T.
- Strangeway R. J.
- Mukherjee J.
- Rager A. C.
- Argall M. R.
- Le Contel Olivier
, 2018, 13, pp.SM13B-2867. We use high-resolution data from the Fast Plasma Instrument (FPI) on board the Magnetosphere Multiscale Mission (MMS) to study a unique dayside asymmetric reconnection event that occurred on 29 December 2016. During this event all four spacecraft observed the electron diffusion region (EDR). Evidence from this event show that electron crescents were produced as EN accelerated magnetosheath electrons near the X-point across the magnetopause where they executed meandering orbits along the reconnection current sheet. This paper provides the first direct measurement of EN acceleration.
Electron Solar Probe Analyzer Design, Operation, and Calibration
- Whittlesey P. L.
- Larson D. E.
- Livi R.
- Kasper J. C.
- Curtis David W.
- Berthomier Matthieu
- Halekas J. S.
- Korreck Kelly E.
, 2018, pp.SH51B-2827. The Electron Solar Probe Analyzer (SPAN-E) instruments are a matching pair of opposing electrostatic analyzer instruments that are a part of the Solar Wind Electrons Alphas and Protons (SWEAP) instrument suite on Parker Solar Probe (PSP). The SPAN-E instruments can measure electrons with energy between 5 eV and 30,000 eV in over 90% of the full sky. The SPAN-E instruments were launched from Florida in August of 2018 and a modicum of data from commissioning has just been returned. This presentation will show the details of the instrument operation and planned observation modes that are possible during the first Parker Solar Probe near-sun encounter, as well as show some of the initial electron data returned from spacecraft commissioning.
Observations of a Small-Scale Flux Rope Next to an EDR at the Dayside Magnetopause
- Hoilijoki S.
- Ergun R.
- Eriksson S.
- Wilder F. D.
- Ahmadi N.
- Schwartz S. J.
- Torbert R. B.
- Le Contel Olivier
- Strangeway R. J.
- Giles B. L.
- Burch J. L.
, 2018, pp.SM13B-2843. Magnetic reconnection is a fundamental plasma process that converts magnetic energy to thermal and kinetic energy of the particles. Previous studies have shown that small-scale magnetic flux ropes often form in secondary magnetic reconnection inside the ion diffusion region, where ions are demagnetized. It has also been shown that these small-scale flux ropes may have a role in the particle acceleration in magnetic reconnection and they might even have an impact on the reconnection rate. With the high cadence multipoint observations provided by Magnetopsheric Multiscale (MMS) mission the details of the small-scale flux ropes and their possible impact on the reconnecting current sheet can be studied. We present results of a dayside magnetopause crossing event where MMS first encounters an electron diffusion region (EDR), where crescent shaped electron velocity distribution functions are observed. Right after the current sheet crossing MMS enters a magnetic structure that has bipolar magnetic field in the direction normal to the current sheet. Inside the structure three of the spacecraft observe an increase in the total magnetic field magnitude and dip in the density. These features suggest that the structure may be a small-scale flux rope being formed adjacent to the current sheet. During this event the MMS spacecraft separation is 8 km, which is much smaller than the ion skin depth (di 40 km) allowing us to investigate the electron scale features of this structure.
Insights from Radio and Plasma Wave Observations During Cassini's Grand Finale
- Kurth William S.
- Averkamp Terrance F.
- Bostrom Rolf
- Canu Patrick
- Cecconi Baptiste
- Cornilleau-Wehrlin Nicole
- Farrell William M.
- Fischer Georg
- Galopeau Patrick H. M.
- Gurnett Donald A.
- Gustafsson G.
- Hadid Lina
- Hospodarsky George B.
- Lamy Laurent
- Lecacheux Alain
- Louarn Philippe
- Macdowall Robert J.
- Menietti John Douglas
- Modolo Ronan
- Morooka Michiko W.
- Pedersen Arne
- Persoon Ann M.
- Sulaiman Ali H.
- Wahlund Jan-Erik
- Ye Shengyi
- Zarka Philippe M.
, 2018, pp.abstract #U21A-07. In its Grand Finale phase, Cassini traversed a region of the Saturnian system not explored in the preceding 12 years in orbit. These high inclination, highly eccentric orbits took Cassini through the source regions of Saturn kilometric radiation (SKR) on auroral magnetic field lines, across field lines that tie the planet to its magnetosphere, the ring system, and through the topside ionosphere near the sub-solar equator just below the ring system. The Radio and Plasma Wave Science (RPWS) instrument studied the conditions in the SKR region that had only been traversed twice in the entire preceding mission. Near 5 kHz intense narrowband emissions are observed in the Z mode at latitudes above about 10°. Plasma wave phenomena known as VLF saucers were observed on field lines threading both Enceladus and the ring system, providing evidence of electron beams and quite possibly currents connecting these members of the Saturnian system to the planet. Determination of the plasma density from the cutoff of whistler mode waves revealed the presence of electron depletions on field lines connected to the main rings, likely relevant to the discussion of 'ring rain'. The RPWS found only very small numbers of micron-sized dust grains in the region between the rings and the atmosphere. Perhaps some of the most important measurements were of plasma densities and temperatures in Saturn's equatorial topside ionosphere, providing important information for understanding how the ring system and the ionosphere interact. These observations revealed small-scale structures in the ionospheric densities and large-scale asymmetries associated with ring shadowing. The ionosphere revealed a new plasma wave phenomenon apparently driven by a lower hybrid instability.
Determination of the MMS path across the magnetopause via magnetic field only
- Manuzzo Roberto
- Belmont Gérard
- Rezeau Laurence
- Califano F.
- Denton R. E.
, 2018, pp.SM31B-14.
Magnetotail dipolarization and dipolarization fronts using spacecraft conjunctions
- Nakamura R.
- Nagai T.
- Nakamura T.
- Baumjohann W.
- Birn Joachim
- Burch J. L.
- Le Contel Olivier
- Giles B. L.
- Escoubet C. Philippe
- Genestreti K. J.
- Sergeev V. A.
- Singer H. J.
- Torbert R. B.
- Varsani A.
, 2018.
Determination of the MMS path across the magnetopause viamagnetic field only
- Manuzzo Roberto
- Rezeau Laurence
- Denton R. E.
- Califano F.
- Belmont Gérard
, 2018.
Magnetosheath Turbulence and its Relationship with Electron Magnetic Reconnection
- Stawarz J. E.
- Eastwood Jonathan P.
- Phan T.
- Burch J. L.
- Ergun R.
- Giles B. L.
- Gershman D. J.
- Le Contel Olivier
- Lindqvist P. A.
- Russell C. T.
- Strangeway R. J.
- Torbert R. B.
- Argall M. R.
- Franci L.
, 2018.
Global comparison of MMS, Cluster and Themis data on January, 4th 2017, with PIC EM code in the vicinity of the Earth's magnetosphere.
- Baraka S. M.
- Le Contel Olivier
- Ben-Jaffel L.
- Scales W.
, 2018, pp.SA41C-3501. IMF orientation values and plasma number densities are surveyed for three spacecraft, MMS, Themis and Cluster. The 4.5 seconds of data survey of MMS and the corresponding times scales of Cluster and Themis are compared with 2 seconds of PIC EM Relativistic code step time. Four IMF orientations are considered in 3D in the code simulations, South, North, Radial and duskdawn directions. The code output data will be transformed to spacecraft positions and compared accordingly. The ions and electrons dy- namics in the foreshock, reconnection, cusps dynamics and other physical parameters are considered in the cur- rent study. The updated version of the code, include, planet tilt 10 deg, space resolution of 0.1 RE and mass ratio of 64
Automatic detection of ICMEs at 1 AU : a deep learning approach
- Nguyen Gautier
- Aunai N.
- Fontaine Dominique
- Le Pennec E.
- Jeandet A.
, 2018, pp.SM31D-3527. Interplanetary Coronal Mass Ejections (ICMEs) are the interplanetarymanifestation of coronal mass ejections.Decades of studies through in situ measurements shed light on theirtypical characteristics : enhanced and smoothly rotating magneticfield, low proton temperature, declining velocity profile and lowplasma beta, etc. However, these features are not all observed for eachICME. In addition, they have a strong variability due to theirintrinsic nature, the way the spacecraft crosses the structure and thedifferent biases introduced by the observer. As a result, there is noreal consensus on how to identify an ICME, leading to disagreements inexisting catalogs which are poorly reproducible or extensible. In this work, we describe an automatic identification method based onconvolutional neural network trained on in situ measurements by theWIND spacecraft over the period 1997-2015. In addition to providing theobserver a fast and reproducible way to identify ICMEs, the algorithmfound about 300 new events. Working without prior knowledge about what ICMEs are other thanlabeled raw data, the method is quite robust and can be used in thefuture to identify signatures of other plasma structures and withmultiple spacecraft.
Characterization of wave-particle interactions in the flux pile-up region of asymmetric reconnection.
- Argall M. R.
- Paulson K. W.
- Ahmadi N.
- Matsui H.
- Leonard T. W.
- Turner D. L.
- Torbert R. B.
- Le Contel Olivier
- Russell C. T.
- Magnes W.
- Strangeway R. J.
- Giles B. L.
- Lindqvist P. A.
- Khotyaintsev Y. V.
- Ergun R.
, 2018, pp.SM13B-2842. We investigate electron whistler wave activity in the flux pile-up region of an asymmetric reconnection event at the magnetopause. The 140Hz waves are right-hand polarized with a wave normal angle of 20 degrees and track the magnetic field strength, consistent with electron whistler waves. Poynting flux direction indicates that the waves were generated at the reconnection site. The waves modulated the flux of 500eV electrons propagating parallel and anti-parallel to the magnetic field, as observed by EDI. Only two of four MMS spacecraft observe similar wave activity, suggesting that the waves are isolated within a narrow flux tube. While it is not possible to use the wave telescope technique, current density produced by 500eV electrons provides a means of estimating the parallel wave vector, k, from a single spacecraft. In addition, we fit the FPI electron parallel energy distribution with a kappa function then use Liouville mapping with 500eV EDI electrons to determine the parallel wave potential, 𝝓, and electric field, E. Combining this with the wave normal angle and Poynting flux direction provides an estimate for the perpendicular components of k and E.
SWEAP takes a scoop: Overview of the coronal and solar wind plasma instruments on Parker Solar Probe
- Whittlesey P. L.
- Livi R.
- Bale S. D.
- Case Anthony W.
- Korreck Kelly E.
- Stevens Michael L.
- Zank G. P.
- Goldstein M. L.
- Richardson J. D.
- Belcher John W.
- Skoug Ruth M.
- Gallagher D. L.
- Berthomier Matthieu
- Chandran Benjamin D. G.
- Bookbinder Jay
- Cirtain Jonathan W.
- Cranmer Steven R.
- Florinski V. A.
- Heerikhuisen J.
- Ho G. C.
- Hu Q.
- Li G.
- Maksimovic M.
- Mcfadden J. P.
- Maruca B. A.
- Pogorelov N. V.
- Szabo Adam
- Wright Jr.
- Kasper J. C.
- Larson D. E.
, 2018, pp.SH51B-2822. The Solar Wind Electrons Alphas and Protons (SWEAP) Investigation on Parker Solar Probe is the four sensor instrument suite responsible for determining the properties of ions and electrons in the coronal and solar wind thermal plasma. The Solar Probe Cup looks directly at the Sun around the Sun to make rapid measurements of ions and electrons flowing directly away from the Sun. The Solar Probe Analyzers look ahead (SPAN-A) and behind (SPAN-B) the spacecraft and make detailed maps of ions and electrons from all other directions in the sky. This talk reviews the SWEAP instrument suite, its commissioning status, and preliminary observations.
Magnetosheath high speed jets and magnetopause observations by Cluster and MMS simultaneously
- Escoubet C. Philippe
- Hwang K.-J.
- Toledo-Redondo Sergio
- Aunai N.
- Dargent Jérémy
- Eastwood Jonathan P.
- Fear R. C.
- Fu H.
- Genestreti K. J.
- Graham Daniel B.
- Khotyaintsev Y. V.
- Lapenta G.
- Lavraud B.
- Norgren C.
- Sibeck David G.
- Varsani A.
- Berchem J.
- Paschmann G.
- Haaland S.
- Dunlop M. W.
- Roberts O.
- Laakso H. E.
- Masson A.
- Turc Lucile
- Carr C. M.
- Dandouras I. S.
- Fazakerley A.
- Nakamura R.
- Burch J. L.
- Giles B. L.
- Pollock C.
- Russell C. T.
- Torbert R. B.
, 2018, pp.SM13B-2840. When the supersonic solar wind encounters the Earth's magnetosphere a shock is formed and the plasma is decelerated and thermalized in the magnetosheath downstream from the shock. Sometimes, however, due to discontinuities in the solar wind, surface waves on the bow shock or ionized dust clouds carried by the solar wind, high speed jets (HSJ) are observed in the magnetosheath. These jets have typically a large Vx component and their pressure can be a few times the solar wind dynamic pressure. They are typically observed downstream from the quasi-parallel bow shock. We use a conjunction of Cluster and MMS, crossing simultaneously the magnetopause, to study the characteristics of these jets and their impact on the magnetopause. At the time of the magnetopause crossing, MMS was located below the magnetic equator at (X,Y,Z)GSM=(8.0,-7.5,-2.9)REwhile Cluster was above the equator at (X,Y,Z)GSM=(9.4,-3.2,6.6)RE. Over a one hour-long interval in the magnetosheath, Cluster observed 15 HSJs. During the same period, MMS observed 7 HSJs and entered the magnetosphere several times. A jet was observed simultaneously on both MMS and Cluster. Since the typical size of jets is around 1 RE, but Cluster and MMS were separated by 10 RE, this indicates that Cluster and MMS may have observed two independent jets. About 1h later, Cluster detected 165 km/s outward magnetopause motion and MMS detected 80 km/s inward motion, simultaneously. The magnetopause crossing was short, around 4s, on all four Cluster spacecraft. On the other hand, the MMS crossing was longer, around 1 min, with a magnetopause oscillating during the crossing. We will investigate the cause of such opposite magnetopause motion and if the HSJs play any role.
MMS Observations of the Kinetic Processes within an Interplanetary Shock
- Schwartz S. J.
- Cohen I. J.
- Ergun R.
- Ahmadi N.
- Goodrich K. A.
- Wei H.
- Anderson B. J.
- Argall M. R.
- Burch J. L.
- Christian E. R.
- Desai M. I.
- Fuselier S. A.
- Giles B. L.
- Le Contel Olivier
- Mauk B.
- Mccomas David J.
- Russell C. T.
- Shuster J. R.
- Strangeway R. J.
- Torbert R. B.
- Vines S. K.
- Westlake J. H.
- Zank G. P.
, 2018.
A new multi-fluid model for space plasma simulations
- Manuzzo Roberto
- Califano F.
- Belmont Gérard
- Rezeau Laurence
- Aunai N.
, 2018, pp.SM11C-2792.
Direct Observations of Whistler-Mode Chorus Modulation of 500eV EDI Electrons by MMS
- Paulson K. W.
- Argall M. R.
- Ahmadi N.
- Matsui H.
- Farrugia C. J.
- Forbes T. G.
- Torbert R. B.
- Vaith H.
- Le Contel Olivier
- Breuillard Hugo
, 2018, pp.SM33C-3596. We present here direct observations of chorus-wave modulated quasi field-aligned electrons using the Electron Drift Instrument (EDI) on board the Magnetospheric Multiscale mission. These events demonstrated fluctuations in the count rates of 500 eV electrons exhibiting the same spectral characteristics as simultaneously observed whistler-mode chorus waves using the on-board search coil magnetometer. As these observations were made by all four spacecraft in a tetrahedral formation, we can use the wave telescope method to verify wave-particle resonance. Additionally, we use the multiple look directions of EDI close to the alignment direction in combination with the sweep of the instrument as the spacecraft spins to generate both pitch angle and gyrophase plots of the fluctuating counts in the wave perturbation frame of reference. We identify periods of gyrophase bunching suggesting active wave-particle interactions. These periods of wave activity were additionally observed to be modulated by Pc5-frequency magnetic perturbations, some of which have been identified as mirror-mode structures. The spacecraft encountered these mirror-mode structures just inside of the duskside magnetopause.
Measuring energy conversion in near-Earth space plasmas with MMS
- Lavraud B.
- Fadanelli S.
- Jacquey C.
- Califano F.
- Eastwood Jonathan P.
- Grigorenko E. E.
- Penou E.
- Toledo-Redondo Sergio
- Vernisse Y.
- Gershman D. J.
- Dorelli J. C.
- Pollock C. J.
- Giles B. L.
- Avanov L. A.
- Burch J. L.
- Chen L. J.
- Coffey V. N.
- Ergun R.
- Farrugia C. J.
- Fuselier S. A.
- Genot V. N.
- Hasegawa H.
- Kacem I.
- Khotyaintsev Y. V.
- Le Contel Olivier
- Moore T. E.
- Nakamura R.
- Paterson W. R.
- Phan T.
- Rager A. C.
- Russell C. T.
- Saito Y.
- Sauvaud J.-A.
- Schiff C.
- Schwartz S. J.
- Smith S. E.
- Torbert R. B.
- Wang S.
- Yokota S.
, 2018.
Turbulence Studies using MMS: data issues and physics
- Bandyopadhyay R.
- Matthaeus W. H.
- Chasapis A.
- Chhiber R.
- Parashar T.
- Maruca B. A.
- Shay M. A.
- Schwartz S. J.
- Eriksson S.
- Le Contel Olivier
- Breuillard Hugo
- Burch J. L.
- Moore T. E.
- Pollock C.
- Giles B. L.
- Dorelli J. C.
- Gershman D. J.
- Torbert R. B.
- Russell C. T.
- Strangeway R. J.
, 2018, pp.SH21C-3294. Magnetospheric Multiscale (MMS) Mission offers measurements of magnetic field, proton and electron moments spanning a broad range of length-scales, from energy containing scales to kinetic scales. The very high time-resolution of the plasma instruments onboard MMS along with the availability of simultaneous measurements from four spacecraft, separated by sub-proton scale distances, make MMS observations an excellent case for study of multi-scale turbulence in near-Earth space plasmas. We calculate the energy transfer rate in the Earth's magnetosheath using two different methods at separate scales. A Karman-Howarth decay phenomenology gives the global energy budget at the energy containing scales. An estimation of inertial range cascade rate is made using Politano-Pouqet third-order law for MHD. We find that the estimates of the energy transfer rates at the large scales and in the inertial scales agree well with each other, providing a confirmation of the assumption of constant energy cascade across those scales. We further measure the incompressive channel of the cascade rate at kinetic scales by evaluating the classical incompressible third-order law at the kinetic scales, using a mutil-spacecraft technique. To use MMS data in the pristine solar wind some processing is required. We provide a procedure to use the measurements of FPI moments in the pristine solar wind. After processing the data, we measure the incompressive energy transfer rate in the solar wind using the third-order law, similar to the magnetosheath case. We find that the energy transfer rate in the magnetosheath is about 1000 times larger than the transfer rate in the solar wind. The higher rate of energy decay rate in the magnetosheath is consistent with the fact the plasma in the sheath is hotter than the solar wind plasma.

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