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Chen LJ, Wang S, Le Contel O, Rager A, Hesse M, Drake J, Dorelli J, Ng J, Bessho N, Graham D, Wilson LB, Moore T, Giles B, Paterson W, Lavraud B, Genestreti K, Nakamura R, Khotyaintsev YV, Ergun RE, Torbert RB, Burch J, Pollock C, Russell CT, Lindqvist PA, Avanov L. Lower-Hybrid Drift Waves Driving Electron Nongyrotropic Heating and Vortical Flows in a Magnetic Reconnection Layer. Phys Rev Lett 2020; 125:025103. [PMID: 32701350 DOI: 10.1103/physrevlett.125.025103] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Accepted: 06/11/2020] [Indexed: 06/11/2023]
Abstract
We report measurements of lower-hybrid drift waves driving electron heating and vortical flows in an electron-scale reconnection layer under a guide field. Electrons accelerated by the electrostatic potential of the waves exhibit perpendicular and nongyrotropic heating. The vortical flows generate magnetic field perturbations comparable to the guide field magnitude. The measurements reveal a new regime of electron-wave interaction and how this interaction modifies the electron dynamics in the reconnection layer.
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Affiliation(s)
- L-J Chen
- NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
| | - S Wang
- NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
- University of Maryland, College Park, Maryland 20747, USA
| | - O Le Contel
- CNRS/Ecole Polytechnique/Sorbonne Université/Univ. Paris Sud/Observatoire de Paris, Paris F91128, France
| | - A Rager
- NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
| | - M Hesse
- University of Bergen, Bergen 5020, Norway
| | - J Drake
- University of Maryland, College Park, Maryland 20747, USA
| | - J Dorelli
- NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
| | - J Ng
- NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
- University of Maryland, College Park, Maryland 20747, USA
| | - N Bessho
- NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
- University of Maryland, College Park, Maryland 20747, USA
| | - D Graham
- Swedish Institute of Space Physics, Uppsala SE-75121, Sweden
| | - Lynn B Wilson
- NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
| | - T Moore
- NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
| | - B Giles
- NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
| | - W Paterson
- NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
| | - B Lavraud
- Institut de Recherche en Astrophysique et Planétologie, Université de Toulouse (UPS), CNRS, CNES, Toulouse 31027 Cedex 4, France
| | - K Genestreti
- University of New Hampshire, Durham, New Hampshire 03824, USA
| | - R Nakamura
- Space Research Institute, Austrian Academy of Sciences, Graz A-8042, Austria
| | | | - R E Ergun
- University of Colorado, Boulder, Colorado 80305, USA
| | - R B Torbert
- University of New Hampshire, Durham, New Hampshire 03824, USA
| | - J Burch
- Southwest Research Institute, San Antonio, Texas 78238, USA
| | - C Pollock
- Denali Scientific, Healy, Alaska 99743, USA
| | - C T Russell
- University of California, Los Angeles, Los Angeles, California 90095, USA
| | - P-A Lindqvist
- KTH Royal Institute of Technology, Stockholm SE-11428, Sweden
| | - L Avanov
- NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
- University of Maryland, College Park, Maryland 20747, USA
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da Silva D, Barrie A, Gershman D, Elkington S, Dorelli J, Giles B, Patterson W. Neural Network Repair of Lossy Compression Artifacts in the September 2015 to March 2016 Duration of the MMS/FPI Data Set. J Geophys Res Space Phys 2020; 125:e2019JA027181. [PMID: 32728509 PMCID: PMC7380320 DOI: 10.1029/2019ja027181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Revised: 03/06/2020] [Accepted: 03/19/2020] [Indexed: 06/11/2023]
Abstract
During the September 2015 to March 2016 duration (sometimes referred to as Phase 1A) of the Magnetospheric Multiscale Mission, the Dual Electron Spectrometers (DES) were configured to generously utilize lossy compression. While this maximized the number of velocity distribution functions downlinked, it came at the expense of lost information content for a fraction of the frames. Following this period of lossy compression, the DES was reconfigured in a way that allowed for 95% of the frames to arrive to the ground without loss. Using this high-quality set of frames from on-orbit observations, we compressed and decompressed the frames on the ground to create a side-by-side record of the compression effect. This record was used to drive an optimization method that (a) derived basis functions capable of approximating the lossless sample space and with nonnegative coefficients and (b) fitted a function which maps the lossy frames to basis weights that recreate the frame without compression artifacts. This method is introduced and evaluated in this paper. Data users should expect a higher level of confidence in the absolute scale of density/temperature measurements and notice less sinusoidal bias in the velocity X and Y components (GSE).
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Affiliation(s)
- Daniel da Silva
- Whiting School of EngineeringJohns Hopkins UniversityBaltimoreMDUSA
- NASA Goddard Spaceflight CenterGreenbeltMDUSA
- Trident Vantage SystemsGreenbeltMDUSA
- Laboratory for Atmospheric and Space PhysicsUniversity of Colorado BoulderBoulderCOUSA
| | - A. Barrie
- NASA Goddard Spaceflight CenterGreenbeltMDUSA
- Aurora EngineeringPotomacMDUSA
| | - D. Gershman
- NASA Goddard Spaceflight CenterGreenbeltMDUSA
| | - S. Elkington
- Laboratory for Atmospheric and Space PhysicsUniversity of Colorado BoulderBoulderCOUSA
| | - J. Dorelli
- NASA Goddard Spaceflight CenterGreenbeltMDUSA
| | - B. Giles
- NASA Goddard Spaceflight CenterGreenbeltMDUSA
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Egedal J, Ng J, Le A, Daughton W, Wetherton B, Dorelli J, Gershman D, Rager A. Pressure Tensor Elements Breaking the Frozen-In Law During Reconnection in Earth's Magnetotail. Phys Rev Lett 2019; 123:225101. [PMID: 31868399 DOI: 10.1103/physrevlett.123.225101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Revised: 08/22/2019] [Indexed: 06/10/2023]
Abstract
Aided by fully kinetic simulations, spacecraft observations of magnetic reconnection in Earth's magnetotail are analyzed. The structure of the electron diffusion region is in quantitative agreement with the numerical model. Of special interest, the spacecraft data reveal how reconnection is mediated by off-diagonal stress in the electron pressure tensor breaking the frozen-in law of the electron fluid.
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Affiliation(s)
- J Egedal
- Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - J Ng
- Center for Heliophysics, Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
| | - A Le
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - W Daughton
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - B Wetherton
- Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - J Dorelli
- Heliophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
| | - D Gershman
- Heliophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
| | - A Rager
- Heliophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
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Chen LJ, Wang S, Wilson LB, Schwartz S, Bessho N, Moore T, Gershman D, Giles B, Malaspina D, Wilder FD, Ergun RE, Hesse M, Lai H, Russell C, Strangeway R, Torbert RB, F-Vinas A, Burch J, Lee S, Pollock C, Dorelli J, Paterson W, Ahmadi N, Goodrich K, Lavraud B, Le Contel O, Khotyaintsev YV, Lindqvist PA, Boardsen S, Wei H, Le A, Avanov L. Electron Bulk Acceleration and Thermalization at Earth's Quasiperpendicular Bow Shock. Phys Rev Lett 2018; 120:225101. [PMID: 29906189 DOI: 10.1103/physrevlett.120.225101] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Revised: 03/30/2018] [Indexed: 06/08/2023]
Abstract
Electron heating at Earth's quasiperpendicular bow shock has been surmised to be due to the combined effects of a quasistatic electric potential and scattering through wave-particle interaction. Here we report the observation of electron distribution functions indicating a new electron heating process occurring at the leading edge of the shock front. Incident solar wind electrons are accelerated parallel to the magnetic field toward downstream, reaching an electron-ion relative drift speed exceeding the electron thermal speed. The bulk acceleration is associated with an electric field pulse embedded in a whistler-mode wave. The high electron-ion relative drift is relaxed primarily through a nonlinear current-driven instability. The relaxed distributions contain a beam traveling toward the shock as a remnant of the accelerated electrons. Similar distribution functions prevail throughout the shock transition layer, suggesting that the observed acceleration and thermalization is essential to the cross-shock electron heating.
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Affiliation(s)
- L-J Chen
- NASA, Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
- Department of Astronomy, University of Maryland, College Park, Maryland 20747, USA
| | - S Wang
- NASA, Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
- Department of Astronomy, University of Maryland, College Park, Maryland 20747, USA
| | - L B Wilson
- NASA, Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
| | - S Schwartz
- Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, Colorado 80305, USA
| | - N Bessho
- NASA, Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
- Department of Astronomy, University of Maryland, College Park, Maryland 20747, USA
| | - T Moore
- NASA, Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
| | - D Gershman
- NASA, Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
| | - B Giles
- NASA, Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
| | - D Malaspina
- Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, Colorado 80305, USA
| | - F D Wilder
- Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, Colorado 80305, USA
| | - R E Ergun
- Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, Colorado 80305, USA
| | - M Hesse
- University of Bergen, Bergen 5020, Norway
| | - H Lai
- University of California, Los Angeles, Los Angeles, California 90095, USA
| | - C Russell
- University of California, Los Angeles, Los Angeles, California 90095, USA
| | - R Strangeway
- University of California, Los Angeles, Los Angeles, California 90095, USA
| | - R B Torbert
- Southwest Research Institute, San Antonio, Texas 78238, USA
| | - A F-Vinas
- NASA, Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
| | - J Burch
- Southwest Research Institute, San Antonio, Texas 78238, USA
| | - S Lee
- NASA, Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
| | - C Pollock
- Denali Scientific, Healy, Alaska 99743, USA
| | - J Dorelli
- NASA, Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
| | - W Paterson
- NASA, Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
| | - N Ahmadi
- Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, Colorado 80305, USA
| | - K Goodrich
- Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, Colorado 80305, USA
| | - B Lavraud
- Institut de Recherche en Astrophysique et Planétologie, Université de Toulouse (UPS), CNRS, CNES, Toulouse, 31028 Cedex 4, France
| | - O Le Contel
- Laboratoire de Physique des Plasmas (UMR7648), CNRS/Ecole Polytechnique/Sorbonne Université/Univ. Paris Sud/Observatoire de Paris, Paris, F91128 Palaiseau Cedex, France
| | | | - P-A Lindqvist
- KTH Royal Institute of Technology, Stockholm SE-11428, Sweden
| | - S Boardsen
- NASA, Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
- Department of Astronomy, University of Maryland, College Park, Maryland 20747, USA
| | - H Wei
- University of California, Los Angeles, Los Angeles, California 90095, USA
| | - A Le
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - L Avanov
- NASA, Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
- Department of Astronomy, University of Maryland, College Park, Maryland 20747, USA
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Che H, Schiff C, Le G, Dorelli J, Giles B, Moore T. Quantifying the Effect of Non-Larmor Motion of Electrons on the Pressure Tensor. Phys Plasmas 2018; 25:032101. [PMID: 32905417 PMCID: PMC7473318 DOI: 10.1063/1.5016853] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
In space plasma, various effects of magnetic reconnection and turbulence cause the electron motion to significantly deviate from their Larmor orbits. Collectively these orbits affect the electron velocity distribution function and lead to the appearance of the "non-gyrotropic" elements in the pressure tensor. Quantification of this effect has important applications in space and laboratory plasma, one of which is tracing the electron diffusion region (EDR) of magnetic reconnection in space observations. Three different measures of agyrotropy of pressure tensor have previously been proposed, namely, A∅ e , Dng and Q. The multitude of contradictory measures has caused confusion within the community. We revisit the problem by considering the basic properties an agyrotropy measure should have. We show that A∅ e , Dng and Q are all defined based on the sum of the principle minors (i.e. the rotation invariant I 2) of the pressure tensor. We discuss in detail the problems of I 2-based measures and explain why they may produce ambiguous and biased results. We introduce a new measure AG constructed based on the determinant of the pressure tensor (i.e. the rotation invariant I 3) which does not suffer from the problems of I 2-based measures. We compare AG with other measures in 2 and 3-dimension particle-in-cell magnetic reconnection simulations, and show that AG can effectively trace the EDR of reconnection in both Harris and force-free current sheets. On the other hand, A∅ e does not show prominent peaks in the EDR and part of the separatrix in the force-free reconnection simulations, demonstrating that A∅ e does not measure all the non-gyrotropic effects in this case, and is not suitable for studying magnetic reconnection in more general situations other than Harris sheet reconnection.
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Affiliation(s)
- H Che
- University of Maryland, College Park, MD, 20742, USA
- NASA Goddard Space Flight Center, Greenbelt, MD, 20771, USA
| | - C Schiff
- NASA Goddard Space Flight Center, Greenbelt, MD, 20771, USA
| | - G Le
- NASA Goddard Space Flight Center, Greenbelt, MD, 20771, USA
| | - J Dorelli
- NASA Goddard Space Flight Center, Greenbelt, MD, 20771, USA
| | - B Giles
- NASA Goddard Space Flight Center, Greenbelt, MD, 20771, USA
| | - T Moore
- NASA Goddard Space Flight Center, Greenbelt, MD, 20771, USA
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Egedal J, Le A, Daughton W, Wetherton B, Cassak PA, Burch JL, Lavraud B, Dorelli J, Gershman DJ, Avanov LA. Spacecraft Observations of Oblique Electron Beams Breaking the Frozen-In Law During Asymmetric Reconnection. Phys Rev Lett 2018; 120:055101. [PMID: 29481157 DOI: 10.1103/physrevlett.120.055101] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Indexed: 06/08/2023]
Abstract
Fully kinetic simulations of asymmetric magnetic reconnection reveal the presence of magnetic-field-aligned beams of electrons flowing toward the topological magnetic x line. Within the ∼6d_{e} electron-diffusion region, the beams become oblique to the local magnetic field, providing a unique signature of the electron-diffusion region where the electron frozen-in law is broken. The numerical predictions are confirmed by in situ Magnetospheric Multiscale spacecraft observations during asymmetric reconnection at Earth's dayside magnetopause.
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Affiliation(s)
- J Egedal
- Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - A Le
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - W Daughton
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - B Wetherton
- Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - P A Cassak
- Department of Physics and Astronomy, West Virginia University, Morgantown, West Virginia 26506, USA
| | - J L Burch
- Southwest Research Institute, San Antonio, Texas 78238, USA
| | - B Lavraud
- Institut de Recherche en Astrophysique et Planétologie, Université de Toulouse, UMR 5277, Toulouse, France
| | - J Dorelli
- Heliophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
| | - D J Gershman
- Heliophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
| | - L A Avanov
- Heliophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
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Egedal J, Le A, Daughton W, Wetherton B, Cassak PA, Chen LJ, Lavraud B, Torbert RB, Dorelli J, Gershman DJ, Avanov LA. Spacecraft Observations and Analytic Theory of Crescent-Shaped Electron Distributions in Asymmetric Magnetic Reconnection. Phys Rev Lett 2016; 117:185101. [PMID: 27835028 PMCID: PMC7437547 DOI: 10.1103/physrevlett.117.185101] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Indexed: 06/06/2023]
Abstract
Supported by a kinetic simulation, we derive an exclusion energy parameter E_{X} providing a lower kinetic energy bound for an electron to cross from one inflow region to the other during magnetic reconnection. As by a Maxwell demon, only high-energy electrons are permitted to cross the inner reconnection region, setting the electron distribution function observed along the low-density side separatrix during asymmetric reconnection. The analytic model accounts for the two distinct flavors of crescent-shaped electron distributions observed by spacecraft in a thin boundary layer along the low-density separatrix.
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Affiliation(s)
- J Egedal
- Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - A Le
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - W Daughton
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - B Wetherton
- Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - P A Cassak
- Department of Physics and Astronomy, West Virginia University, Morgantown, West Virginia 26506, USA
| | - L-J Chen
- Heliophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
| | - B Lavraud
- Institut de Recherche en Astrophysique et Planétologie, Université de Toulouse, Toulouse, France, and Centre National de la Recherche Scientifique, UMR 5277, Toulouse, France
| | - R B Torbert
- University of New Hampshire, Durham, New Hampshire 03824, USA
| | - J Dorelli
- Heliophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
| | - D J Gershman
- Heliophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
| | - L A Avanov
- Heliophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
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Karimabadi H, Dorelli J, Roytershteyn V, Daughton W, Chacón L. Flux pileup in collisionless magnetic reconnection: bursty interaction of large flux ropes. Phys Rev Lett 2011; 107:025002. [PMID: 21797613 DOI: 10.1103/physrevlett.107.025002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2011] [Indexed: 05/31/2023]
Abstract
Using fully kinetic simulations of the island coalescence problem for a range of system sizes greatly exceeding kinetic scales, the phenomenon of flux pileup in the collisionless regime is demonstrated. While small islands on the scale of λ ≤ 5 ion inertial length (d(i)) coalesce rapidly and do not support significant flux pileup, coalescence of larger islands is characterized by large flux pileup and a weaker time averaged reconnection rate that scales as √(d(i)/λ) while the peak rate remains nearly independent of island size. For the largest islands (λ = 100d(i)), reconnection is bursty and nearly shuts off after the first bounce, reconnecting ~20% of the available flux.
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Affiliation(s)
- H Karimabadi
- University of California at San Diego, La Jolla, California 92093, USA
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