Medium Energy Neutral Atom (MENA) Imager for the Image Mission

Pollock, C. J.; Asamura, Kazushi; Baldonado, J. R.; Balkey, M. M.; Barker, P. F.; Burch, J. L.; Korpela, E. J.; Cravens, J.; Dirks, G.; Fok, M. C. H.; Funsten, H. O.; Grandé, M.; Gruntman, M.; Hanley, J.; Jahn, J.; Jenkins, M.; Lampton, M.; Marckwordt, Mario; McComas, D. J.; Mukai, T.; Penegor, G.; Pope, S.; Ritzau, S. M.; Schattenburg, Mark L.; Scime, Earl; Skoug, R. M.; Spurgeon, W.; Stecklein, T.; Storms, S. A.; Urdiales, C.; Valek, P. W.; Beek, J.T.M. van; Weidner, S.; Wüest, M.; Young, Michael K.; Zinsmeyer, C.

doi:10.1007/978-94-011-4233-5_5

Cited by 54 publications

(57 citation statements)

References 21 publications

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“…The Two Wide-angle Imaging Neutral-atom Spectrometers (TWINS) (McComas et al, 2009;) are based upon the slit camera concept originally flown on the IMAGE MENA instrument (Pollock et al, 2000). In our study we present TWINS ENA data in two ways: (1) global images and (2) the low-altitude emission (LAE) index .…”

Section: Global Observations: Twins and Amperementioning

confidence: 99%

Magnetosphere dynamics during the 14 November 2012 storm inferred from TWINS, AMPERE, Van Allen Probes, and BATS-R-US–CRCM

et al. 2018

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Abstract. During the 14 November 2012 geomagnetic storm, the Van Allen Probes spacecraft observed a number of sharp decreases ("dropouts") in particle fluxes for ions and electrons of different energies. In this paper, we investigate the global magnetosphere dynamics and magnetosphereionosphere (M-I) coupling during the dropout events using multipoint measurements by Van Allen Probes, TWINS, and AMPERE together with the output of the two-way coupled global BATS-R-US-CRCM model. We find different behavior for two pairs of dropouts. For one pair, the same pattern was repeated: (1) weak nightside Region 1 and 2 Birkeland currents before and during the dropout; (2) intensification of Region 2 currents after the dropout; and (3) a particle injection detected by TWINS after the dropout. The model predicted similar behavior of Birkeland currents. TWINS low-altitude emissions demonstrated high variability during these intervals, indicating high geomagnetic activity in the near-Earth tail region. For the second pair of dropouts, the structure of both Birkeland currents and ENA emissions was relatively stable. The model also showed quasi-stationary behavior of Birkeland currents and simulated ENA emissions with gradual ring current buildup. We confirm that the first pair of dropouts was caused by large-scale motions of the OCB (open-closed boundary) during substorm activity. We show the new result that this OCB motion was associated with global changes in Birkeland (M-I coupling) currents and strong modulation of low-altitude ion precipitation. The second pair of dropouts is the result of smaller OCB disturbances not related to magnetospheric substorms. The local observations of the first pair of dropouts result from a global magnetospheric reconfiguration, which is manifested by ion injections and enhanced ion precipitation detected by TWINS and changes in the structure of Birkeland currents detected by AMPERE. This study demonstrates that multipoint measurements along with the global model results enable the reconstruction of a more complete system-level picture of the dropout events and provides insight into M-I coupling aspects that have not previously been investigated.

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Section: Global Observations: Twins and Amperementioning

confidence: 99%

Magnetosphere dynamics during the 14 November 2012 storm inferred from TWINS, AMPERE, Van Allen Probes, and BATS-R-US–CRCM

et al. 2018

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“…The similar IMAGE MENA instrument [Pollock et al, 2000] uses the method of Henderson et al [2005] in which a fit to the measured energy spectra for each angle bin is used to determine the flux at a given energy. This was necessary for MENA owing to its limited telemetry for TOF.…”

Section: A1 Ena Binningmentioning

confidence: 99%

Two Wide‐Angle Imaging Neutral‐Atom Spectrometers and Interstellar Boundary Explorer energetic neutral atom imaging of the 5 April 2010 substorm

et al. 2012

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[1] This study is the first to combine energetic neutral atom (ENA) observations from Two Wide-Angle Imaging Neutral-Atom Spectrometers (TWINS) and Interstellar Boundary Explorer (IBEX). Here we examine the arrival of an interplanetary shock and the subsequent geomagnetically effective substorm on 5 April 2010, which was associated with the Galaxy 15 communications satellite anomaly. IBEX shows sharply enhanced ENA emissions immediately upon compression of the dayside magnetosphere at 08:26:17+/À9 s UT. The compression drove a markedly different spectral shape for the dayside emissions, with a strong enhancement at energies >1 keV, which persisted for hours after the shock arrival, consistent with the higher solar wind speed, density, and dynamic pressure ($10 nPa) after the shock. TWINS ENA observations indicate a slower response of the ring current and precipitation of ring current ions as low-altitude emissions $15 min later, with the >50 keV ion precipitation leading the <10 keV precipitation by $20 min. These observations suggest internal magnetospheric processes are occurring after compression of the magnetosphere and before the ring current ions end up in the loss cone and precipitate into the ionosphere. We also compare MHD simulation results with both the TWINS and IBEX ENA observations; while the overall fluxes and distributions of emissions were generally similar, there were significant quantitative differences. Such differences emphasize the complexity of the magnetospheric system and importance of the global perspective for macroscopic magnetospheric studies. Finally, Appendix A documents important details of the TWINS data processing, including improved binning procedures, smoothing of images to a given level of statistical accuracy, and differential background subtraction.

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“…[9] The TWINS imagers are based upon the "slit camera" concept [McComas et al, 1998] originally flown for the MENA instrument [Pollock et al, 2000] on the IMAGE satellite. This design provides the very large aperture, and hence geometric factor, required to properly image ENAs across the critical energy range from $1 keV to several 10s of keV.…”

Section: Twins Ena Instrumentsmentioning

confidence: 99%

Evolution of CIR storm on 22 July 2009

et al. 2012

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[1] Global images of ion intensities are deconvolved from TWINS ENA images during the main and recovery phase of a CIR storm on 22 July 2009. The global spatial ion images taken at different times, along with solar wind data, geomagnetic activity indices, geosynchronous orbit observations, and in situ measurements from the THEMIS mission provide a picture of the evolution of the ring current during both the main phase and early recovery phase of the storm. Major features of the evolution are consistent with expectations based upon time dependent geomagnetic indices, e.g., SYM/H and ASY/H, and geosynchronous orbit detection of dipolarizations from GOES 11 and 12. Direct comparisons are made with in situ THEMIS ESA and SST spectral measurements. The peak energy of the ion spectrum in the ring current is seen to decrease in the recovery phase. The time evolution of the ion energy spectra over the range from 2.5 to 97.5 keV at the spatial peaks of the ring current in the inner magnetosphere obtained from ENA images is presented for the first time.

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Medium Energy Neutral Atom (MENA) Imager for the Image Mission

Cited by 54 publications

References 21 publications

Magnetosphere dynamics during the 14 November 2012 storm inferred from TWINS, AMPERE, Van Allen Probes, and BATS-R-US–CRCM

Magnetosphere dynamics during the 14 November 2012 storm inferred from TWINS, AMPERE, Van Allen Probes, and BATS-R-US–CRCM

Two Wide‐Angle Imaging Neutral‐Atom Spectrometers and Interstellar Boundary Explorer energetic neutral atom imaging of the 5 April 2010 substorm

Evolution of CIR storm on 22 July 2009

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