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B H Mauk - One of the best experts on this subject based on the ideXlab platform.
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observatIon and interpretatIon of Energetic Ion conics in jupiter s polar magnetosphere
Geophysical Research Letters, 2017Co-Authors: G Clark, B H Mauk, C Paranicas, S. E. Jaskulek, C. E. Schlemm, L. E. Brown, D K Haggerty, P Kollmann, A M Rymer, C KimAbstract:NASA's Juno spacecraft successfully completed its first science polar pass over Jupiter's northern and southern aurora, with all the instruments powered, on 27 August 2016. ObservatIons of conical Energetic proton distributIons at low altitudes (<6 RJ) over the northern polar regIon are interpreted as resulting from transversely (to the local magnetic field lines) accelerated H+ at a positIon planetward of the point of observatIon. The proton conics were observed within a broad regIon of upward beaming electrons and were accompanied by broadband low-frequency wave emissIons as well as low-altitude trapped magnetospheric protons and heavy Ions. The characteristic energies associated with these accelerated Ion conics are ~100 times more Energetic than similar distributIons observed in the Earth's auroral regIon and similar in energy to those found at Saturn. In additIon, the Ion conics also exhibited pitch angle dispersIon with time that is interpreted as a consequence of the structure of the source locatIon. Mapping these distributIons along magnetic field lines connected from the spacecraft to the Ionosphere suggests that the source regIon exists at altitudes between ~3 and 5 RJ. These new and exciting observatIons of accelerated Ions over the polar regIon of Jupiter open up new areas for comparative planetary auroral physics.
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observatIons of Energetic particle escape at the magnetopause early results from the mms Energetic Ion spectrometer eis
Geophysical Research Letters, 2016Co-Authors: I J Cohen, B H Mauk, D L Turner, J F Fennell, B J Anderson, J H Westlake, D G Sibeck, B L Giles, C J Pollock, J. B. BlakeAbstract:Energetic (greater than tens of keV) magnetospheric particle escape into the magnetosheath occurs commonly, irrespective of conditIons that engender reconnectIon and boundary-normal magnetic fields. A signature observed by the Magnetospheric Multiscale (MMS) missIon, simultaneous monohemispheric streaming of multiple species (electrons, H+, Hen+), is reported here as unexpectedly common in the dayside, dusk quadrant of the magnetosheath even though that regIon is thought to be drift-shadowed from Energetic electrons. This signature is sometimes part of a pitch angle distributIon evolving from symmetric in the magnetosphere, to asymmetric approaching the magnetopause, to monohemispheric streaming in the magnetosheath. While monohemispheric streaming in the magnetosheath may be possible without a boundary-normal magnetic field, the additIonal pitch angle depletIon, particularly of electrons, on the magnetospheric side requires one. ObservatIons of this signature in the dayside dusk sector imply that the static picture of magnetospheric drift-shadowing is inappropriate for Energetic particle dynamics in the outer magnetosphere.
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The Energetic Particle Detector (EPD) InvestigatIon and the Energetic Ion Spectrometer (EIS) for the Magnetospheric Multiscale (MMS) MissIon
Space Science Reviews, 2016Co-Authors: B H Mauk, J. B. Blake, D. N. Baker, J. H. Clemmons, G. D. Reeves, H. E. Spence, S. E. Jaskulek, C. E. Schlemm, L. E. Brown, S. A. CooperAbstract:The Energetic Particle Detector (EPD) InvestigatIon is one of 5 fields-and-particles investigatIons on the Magnetospheric Multiscale (MMS) missIon. MMS comprises 4 spacecraft flying in close formatIon in highly elliptical, near-Earth-equatorial orbits targeting understanding of the fundamental physics of the important physical process called magnetic reconnectIon using Earth’s magnetosphere as a plasma laboratory. EPD comprises two sensor types, the Energetic Ion Spectrometer (EIS) with one instrument on each of the 4 spacecraft, and the Fly’s Eye Energetic Particle Spectrometer (FEEPS) with 2 instruments on each of the 4 spacecraft. EIS measures Energetic Ion energy, angle and elemental compositIonal distributIons from a required low energy limit of 20 keV for protons and 45 keV for oxygen Ions, up to >0.5 MeV (with capabilities to measure up to >1 MeV). FEEPS measures instantaneous all sky images of Energetic electrons from 25 keV to >0.5 MeV, and also measures total Ion energy distributIons from 45 keV to >0.5 MeV to be used in conjunctIon with EIS to measure all sky Ion distributIons. In this report we describe the EPD investigatIon and the details of the EIS sensor. Specifically we describe EPD-level science objectives, the science and measurement requirements, and the challenges that the EPD team had in meeting these requirements. Here we also describe the design and operatIon of the EIS instruments, their calibrated performances, and the EIS in-flight and ground operatIons. Blake et al. (The Flys Eye Energetic Particle Spectrometer (FEEPS) contributIon to the Energetic Particle Detector (EPD) investigatIon of the Magnetospheric Magnetoscale (MMS) MissIon, this issue ) describe the design and operatIon of the FEEPS instruments, their calibrated performances, and the FEEPS in-flight and ground operatIons. The MMS spacecraft will launch in early 2015, and over its 2-year missIon will provide comprehensive measurements of magnetic reconnectIon at Earth’s magnetopause during the 18 months that comprise orbital phase 1, and magnetic reconnectIon within Earth’s magnetotail during the about 6 months that comprise orbital phase 2.
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comparative investigatIon of the Energetic Ion spectra comprising the magnetospheric ring currents of the solar system
Journal of Geophysical Research, 2014Co-Authors: B H MaukAbstract:Investigated here are factors that control the intensities and shapes of Energetic Ion spectra that make up the ring current populatIons of the strongly magnetized planets of the solar system, specifically those of Earth, Jupiter, Saturn, Uranus, and Neptune. Following a previous and similar comparative investigatIon of radiatIon belt electrons, we here turn our attentIon to Ions. Specifically, we examine the possible role of the differential Ion Kennel-Petschek limit, as moderated by Electromagnetic Ion Cyclotron (EMIC) waves, as a standard for comparing the most intense Ion spectra within the strongly magnetized planetary magnetospheres. In carrying out this investigatIon, the substantial complexities engendered by the very different Ion compositIon distributIons of these diverse magnetospheres must be addressed, given that the dispersIon properties of the EMIC waves are strongly determined by the Ion compositIon of the plasmas within which the waves propagate. Chosen for comparison are the Ion spectra within these systems that are the most intense observed, specifically at 100 keV and 1 MeV. We find that Earth and Jupiter are unique in having their most intense Ion spectra likely limited and sculpted by the Kennel-Petschek process. The Ion spectra of Saturn, Uranus, and Neptune reside far below their respective limits and are likely limited by interactIons with gas and dust (Saturn) and by the absence of robust Ion acceleratIon processes (Uranus and Neptune). SuggestIons are provided for further testing the efficacy of the differential Kennel-Petschek limit for Ions using the Van Allen Probes.
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ring current at saturn Energetic particle pressure in saturn s equatorial magnetosphere measured with cassini mimi
Geophysical Research Letters, 2007Co-Authors: N Sergis, D G Mitchell, B H Mauk, E C Roelof, S M Krimigis, N Krupp, D C Hamilton, M K DoughertyAbstract:[1] The Magnetospheric Imaging Instrument (MIMI) on the Cassini spacecraft provides measurements of the Energetic Ion populatIon within the magnetosphere of Saturn. Energetic Ion directIonal intensities, energy spectra and Ion compositIon, are measured by the Charge Energy Mass Spectrometer (CHEMS) over the range ∼3 to 236 keV per charge and by the Low Energy Magnetospheric Measurements System (LEMMS) for Ions in the range 0.024 10 RS; (2) most particle pressure is contained in the range of 10 < E < 150 keV; and (3) in the high beta regIon 10 < L < 19, where the apparent ring current resides, oxygen generally contributes more than 50% of the total particle pressure. The results demonstrate that typical assumptIons of MHD models, whereby particle pressure is presumed to reside with the cold plasma, are not supported by the data.
G J Kramer - One of the best experts on this subject based on the ideXlab platform.
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enhanced localized Energetic Ion losses resulting from single pass interactIons with alfven eigenmodes
Physical Review Letters, 2013Co-Authors: X Chen, W W Heidbrink, D C Pace, R K Fisher, G J Kramer, R Nazikian, M E Austin, C C Petty, M A Van ZeelandAbstract:We report the first observatIon of prompt neutral beam-Ion losses due to nonresonant scattering induced by toroidal and reversed shear Alfven eigenmodes in the DIII-D tokamak. The coherent losses are of full energy beam Ions expelled from the plasma on their first poloidal orbit. The first-orbit loss mechanism causes enhanced, concentrated losses on the first wall exceeding nominal levels of prompt losses. The loss amplitude scales linearly with the mode amplitude. The data provide a novel and direct measure of the radial excursIon or scatter of particles induced by individual modes and may shed light on the mechanism for the scattering of Energetic particles in interstellar medium.
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Energetic Ion transport by abrupt large amplitude event induced by negative Ion based neutral beam injectIon in the jt 60u
Nuclear Fusion, 2005Co-Authors: M Ishikawa, M Takechi, K Shinohara, Y Kusama, C Z Cheng, G Matsunaga, Y Todo, N N Gorelenkov, G J Kramer, R NazikianAbstract:To investigate Energetic Ion transport induced by bursting modes in the frequency range of Alfven eigenmodes, which is called abrupt large-amplitude events (ALEs) driven by negative-Ion-based neutral beam (N-NB) injectIon, neutron emissIon profile measurement and charge exchange (CX) neutral particle (flux) measurement using a natural diamond detector have been performed simultaneously in JT-60U. It is found from the CX neutral particle (flux) measurement that Energetic neutral particles in a limited energy range (100–370 keV) are enhanced due to ALEs, and the neutron radial profile is flattened. The change in the Energetic Ion density profile inferred from these measurements indicates that ALEs expel Energetic Ions from the core regIon of the plasma and induce both redistributIon and loss of Energetic Ions. It has been shown that the energy range of transported Energetic Ions is consistent with a resonance conditIon between Energetic Ions and ALEs, and the Energetic Ion transport results from the resonant interactIon between Energetic Ions and ALEs. Further, a fractIon of the Energetic Ion loss has been quantitatively estimated to be ~4%.
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characteristics of alfven eigenmodes burst modes and chirping modes in the alfven frequency range driven by negative Ion based neutral beam injectIon in jt 60u
Nuclear Fusion, 1999Co-Authors: Y Kusama, K Shinohara, G J Kramer, H Kimura, M Saigusa, T Ozeki, K Tobita, T Oikawa, T Kondoh, M MoriyamaAbstract:The excitatIon and stabilizatIon of Alfv?n eigenmodes and their impact on Energetic Ion confinement were investigated with negative Ion based neutral beam injectIon at 330-360?keV into weak or reversed magnetic shear plasmas on JT-60U. Toroidicity induced Alfv?n eigenmodes (TAEs) were observed in weak shear plasmas with ?h ? 0.1% and 0.4 ? vb||/vA ? 1. The stability of TAEs is consistent with predictIons by the NOVA-K code. New burst modes and chirping modes were observed in the higher ? regime of ?h ? 0.2%. The effect of TAEs, burst modes and chirping modes on fast Ion confinement has been found to be small so far. It was found that a strongly reversed shear plasma with internal transport barrier suppresses AEs.
R Nazikian - One of the best experts on this subject based on the ideXlab platform.
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enhanced localized Energetic Ion losses resulting from single pass interactIons with alfven eigenmodes
Physical Review Letters, 2013Co-Authors: X Chen, W W Heidbrink, D C Pace, R K Fisher, G J Kramer, R Nazikian, M E Austin, C C Petty, M A Van ZeelandAbstract:We report the first observatIon of prompt neutral beam-Ion losses due to nonresonant scattering induced by toroidal and reversed shear Alfven eigenmodes in the DIII-D tokamak. The coherent losses are of full energy beam Ions expelled from the plasma on their first poloidal orbit. The first-orbit loss mechanism causes enhanced, concentrated losses on the first wall exceeding nominal levels of prompt losses. The loss amplitude scales linearly with the mode amplitude. The data provide a novel and direct measure of the radial excursIon or scatter of particles induced by individual modes and may shed light on the mechanism for the scattering of Energetic particles in interstellar medium.
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Energetic Ion transport by abrupt large amplitude event induced by negative Ion based neutral beam injectIon in the jt 60u
Nuclear Fusion, 2005Co-Authors: M Ishikawa, M Takechi, K Shinohara, Y Kusama, C Z Cheng, G Matsunaga, Y Todo, N N Gorelenkov, G J Kramer, R NazikianAbstract:To investigate Energetic Ion transport induced by bursting modes in the frequency range of Alfven eigenmodes, which is called abrupt large-amplitude events (ALEs) driven by negative-Ion-based neutral beam (N-NB) injectIon, neutron emissIon profile measurement and charge exchange (CX) neutral particle (flux) measurement using a natural diamond detector have been performed simultaneously in JT-60U. It is found from the CX neutral particle (flux) measurement that Energetic neutral particles in a limited energy range (100–370 keV) are enhanced due to ALEs, and the neutron radial profile is flattened. The change in the Energetic Ion density profile inferred from these measurements indicates that ALEs expel Energetic Ions from the core regIon of the plasma and induce both redistributIon and loss of Energetic Ions. It has been shown that the energy range of transported Energetic Ions is consistent with a resonance conditIon between Energetic Ions and ALEs, and the Energetic Ion transport results from the resonant interactIon between Energetic Ions and ALEs. Further, a fractIon of the Energetic Ion loss has been quantitatively estimated to be ~4%.
C M S Cohen - One of the best experts on this subject based on the ideXlab platform.
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Magnetic field line random walk and solar Energetic particle path lengths
'EDP Sciences', 2021Co-Authors: R Chhiber, C M S Cohen, W H Matthaeus, D Ruffolo, W Sonsrettee, P Tooprakai, A Seripienlert, P Chuychai, A V Usmanov, M L GoldsteinAbstract:Context. In 2020 May-June, six solar Energetic Ion events were observed by the Parker Solar Probe/IS⊙IS instrument suite at ≈0.35 AU from the Sun. From standard velocity-dispersIon analysis, the apparent Ion path length is ≈0.625 AU at the onset of each event. Aims. We develop a formalism for estimating the path length of random-walking magnetic field lines to explain why the apparent Ion path length at an event onset greatly exceeds the radial distance from the Sun for these events. Methods. We developed analytical estimates of the average increase in path length of random-walking magnetic field lines, relative to the unperturbed mean field. Monte Carlo simulatIons of field line and particle trajectories in a model of solar wind turbulence were used to validate the formalism and study the path lengths of particle guiding-center and full-orbital trajectories. The formalism was implemented in a global solar wind model, and the results are compared with Ion path lengths inferred from IS⊙IS observatIons. Results. Both a simple estimate and a rigorous theoretical formulatIon are obtained for field-lines’ path length increase as a functIon of path length along the large-scale field. From simulated field line and particle trajectories, we find that particle guiding centers can have path lengths somewhat shorter than the average field line path length, while particle orbits can have substantially longer path lengths due to their gyromotIon with a nonzero effective pitch angle. ConclusIons. The long apparent path length during these solar Energetic Ion events can be explained by (1) a magnetic field line path length increase due to the field line random walk and (2) particle transport about the guiding center with a nonzero effective pitch angle due to pitch angle scattering. Our formalism for computing the magnetic field line path length, accounting for turbulent fluctuatIons, may be useful for applicatIon to solar particle transport in general
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magnetic field line random walk and solar Energetic particle path lengths stochastic theory and psp isois observatIon
arXiv: Solar and Stellar Astrophysics, 2020Co-Authors: R Chhiber, C M S Cohen, W H Matthaeus, D Ruffolo, W Sonsrettee, P Tooprakai, A Seripienlert, P Chuychai, A V Usmanov, M L GoldsteinAbstract:Context:In 2020 May-June, six solar Energetic Ion events were observed by the Parker Solar Probe/ISoIS instrument suite at 0.35 AU from the Sun. From standard velocity-dispersIon analysis, the apparent Ion path length is 0.625 AU at the onset of each event. Aims:We develop a formalism for estimating the path length of random-walking magnetic field lines, to explain why the apparent Ion pathlength at event onset greatly exceeds the radial distance from the Sun for these events. Methods:We developed analytical estimates of the average increase in pathlength of random-walking magnetic field lines, relative to the unperturbed mean field. Monte Carlo simulatIons of fieldline and particle trajectories in a model of solar wind turbulence are used to validate the formalism and study the path lengths of particle guiding-center and full-orbital trajectories. The formalism is implemented in a global solar wind model, and results are compared with Ion pathlengths inferred from ISoIS observatIons. Results:Both a simple estimate and a rigorous theoretical formulatIon are obtained for fieldlines' pathlength increase as a functIon of pathlength along the large-scale field. From simulated fieldline and particle trajectories, we find that particle guiding centers can have pathlengths somewhat shorter than the average fieldline pathlength, while particle orbits can have substantially larger pathlengths due to their gyromotIon with a nonzero effective pitch angle. ConclusIons:The long apparent path length during these solar Energetic Ion events can be explained by 1) a magnetic field line path length increase due to the field line random walk, and 2) particle transport about the guiding center with a nonzero effective pitch angle. Our formalism for computing the magnetic field line path length, accounting for turbulent fluctuatIons, may be useful for applicatIon to solar particle transport in general.
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the very unusual interplanetary coronal mass ejectIon of 2012 july 23 a blast wave mediated by solar Energetic particles
The Astrophysical Journal, 2013Co-Authors: C T Russell, R A Mewaldt, J G Luhmann, G M Mason, T T Von Rosenvinge, C M S Cohen, R A Leske, R Gomezherrero, A Klassen, A B GalvinAbstract:The giant, superfast, interplanetary coronal mass ejectIon, detected by STEREO A on 2012 July 23, well away from Earth, appears to have reached 1 AU with an unusual set of leading bow waves resembling in some ways a subsonic interactIon, possibly due to the high pressures present in the very Energetic particles produced in this event. Eventually, a front of record high-speed flow reached STEREO. The unusual behavior of this event is illustrated using the magnetic field, plasma, and Energetic Ion observatIons obtained by STEREO. Had the Earth been at the locatIon of STEREO, the large southward-oriented magnetic field component in the event, combined with its high speed, would have produced a record storm.
Y Kusama - One of the best experts on this subject based on the ideXlab platform.
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Energetic Ion transport by abrupt large amplitude event induced by negative Ion based neutral beam injectIon in the jt 60u
Nuclear Fusion, 2005Co-Authors: M Ishikawa, M Takechi, K Shinohara, Y Kusama, C Z Cheng, G Matsunaga, Y Todo, N N Gorelenkov, G J Kramer, R NazikianAbstract:To investigate Energetic Ion transport induced by bursting modes in the frequency range of Alfven eigenmodes, which is called abrupt large-amplitude events (ALEs) driven by negative-Ion-based neutral beam (N-NB) injectIon, neutron emissIon profile measurement and charge exchange (CX) neutral particle (flux) measurement using a natural diamond detector have been performed simultaneously in JT-60U. It is found from the CX neutral particle (flux) measurement that Energetic neutral particles in a limited energy range (100–370 keV) are enhanced due to ALEs, and the neutron radial profile is flattened. The change in the Energetic Ion density profile inferred from these measurements indicates that ALEs expel Energetic Ions from the core regIon of the plasma and induce both redistributIon and loss of Energetic Ions. It has been shown that the energy range of transported Energetic Ions is consistent with a resonance conditIon between Energetic Ions and ALEs, and the Energetic Ion transport results from the resonant interactIon between Energetic Ions and ALEs. Further, a fractIon of the Energetic Ion loss has been quantitatively estimated to be ~4%.
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characteristics of alfven eigenmodes burst modes and chirping modes in the alfven frequency range driven by negative Ion based neutral beam injectIon in jt 60u
Nuclear Fusion, 1999Co-Authors: Y Kusama, K Shinohara, G J Kramer, H Kimura, M Saigusa, T Ozeki, K Tobita, T Oikawa, T Kondoh, M MoriyamaAbstract:The excitatIon and stabilizatIon of Alfv?n eigenmodes and their impact on Energetic Ion confinement were investigated with negative Ion based neutral beam injectIon at 330-360?keV into weak or reversed magnetic shear plasmas on JT-60U. Toroidicity induced Alfv?n eigenmodes (TAEs) were observed in weak shear plasmas with ?h ? 0.1% and 0.4 ? vb||/vA ? 1. The stability of TAEs is consistent with predictIons by the NOVA-K code. New burst modes and chirping modes were observed in the higher ? regime of ?h ? 0.2%. The effect of TAEs, burst modes and chirping modes on fast Ion confinement has been found to be small so far. It was found that a strongly reversed shear plasma with internal transport barrier suppresses AEs.