The IMAP-Ultra Energetic Neutral Atom (ENA) Imager

Matina Gkioulidou; G. B. Clark; D. G. Mitchell; A. R. Dupont; K. L. Anderson; S. Begley; M. Bzowski; E. R. Christian; C. E. Cook; A. B. Crew; M. J. Cully; R. DeMajistre; T. J. Diaz; R. J. Drexler; N. T. Dutton; C. J. Gingrich; J. R. Hayes; C. M. Huber; J. Hutcheson; S. E. Jaskulek; P. Kollmann; M. T. LeBlanc; J. Lees; D. J. McComas; K. S. Nelson; C. W. Parker; D. B. Reisenfeld; E. A. Rollend; C. E. Schlemm; N. A. Schwadron; R. Verrill; J. Yen; J. Yin

doi:10.1007/s11214-025-01256-5

The IMAP-Ultra Energetic Neutral Atom (ENA) Imager

Matina Gkioulidou
, G. B. Clark
, D. G. Mitchell
, A. R. Dupont
, K. L. Anderson
, S. Begley
, M. Bzowski
, E. R. Christian
, C. E. Cook
, A. B. Crew
, M. J. Cully
, R. DeMajistre
, T. J. Diaz
, R. J. Drexler
, N. T. Dutton
, C. J. Gingrich
, J. R. Hayes
, C. M. Huber
, J. Hutcheson
, S. E. Jaskulek

P. Kollmann, M. T. LeBlanc, J. Lees, D. J. McComas, K. S. Nelson, C. W. Parker, D. B. Reisenfeld, E. A. Rollend, C. E. Schlemm, N. A. Schwadron, R. Verrill, J. Yen, J. Yin

Astrophysical Sciences

Research output: Contribution to journal › Review article › peer-review

5 Scopus citations

Abstract

NASA’s Interstellar Mapping and Acceleration Probe (IMAP), a spinner spacecraft in orbit around L1, is taking in situ observations of thermal, pickup, and energetic particles, while simultaneously remotely sensing the effects that these particles have in the outer heliosphere, by measuring Energetic Neutral Atoms (ENA) emissions produced by neutralized energetic ions when they charge exchange with interstellar neutral particles in that region. The IMAP-Ultra instrument (Ultra), one of the three ENA imagers on IMAP, measures the emission of the highest energy ENAs produced in the heliosheath and beyond. Ultra consists of two sensors with one sensor angled at 90° (Ultra₉₀) and the other at 45° (Ultra₄₅) from the spacecraft’s spin axis. Ultra was designed and optimized to measure hydrogen (H) ENAs from 5 – 40 keV, but the sensors have been demonstrated to measure H from ∼3 – 300 keV. Additionally, Ultra’s large ∼96° × 120° field of view (FoV) is capable of achieving angular resolutions ≤ 6° FWHM for ≥ 10 keV for H ENAs. Ultra provides high spatial resolution, full heliosphere maps, detecting changes in the spatial distribution of ENAs, on time scales sufficient to track both solar cycle as well as other major variations.

Original language	English (US)
Article number	4
Journal	Space Science Reviews
Volume	222
Issue number	1
DOIs	https://doi.org/10.1007/s11214-025-01256-5
State	Published - Jan 2026

All Science Journal Classification (ASJC) codes

Astronomy and Astrophysics
Space and Planetary Science

Keywords

Energetic neutral atoms
Heliosheath
Heliosphere
IMAP
Interstellar medium
Termination shock

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10.1007/s11214-025-01256-5

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Gkioulidou, M., Clark, G. B., Mitchell, D. G., Dupont, A. R., Anderson, K. L., Begley, S., Bzowski, M., Christian, E. R., Cook, C. E., Crew, A. B., Cully, M. J., DeMajistre, R., Diaz, T. J., Drexler, R. J., Dutton, N. T., Gingrich, C. J., Hayes, J. R., Huber, C. M., Hutcheson, J., ... Yin, J. (2026). The IMAP-Ultra Energetic Neutral Atom (ENA) Imager. Space Science Reviews, 222(1), Article 4. https://doi.org/10.1007/s11214-025-01256-5

@article{a1ba688fab7247759b8813838001448c,

title = "The IMAP-Ultra Energetic Neutral Atom (ENA) Imager",

abstract = "NASA{\textquoteright}s Interstellar Mapping and Acceleration Probe (IMAP), a spinner spacecraft in orbit around L1, is taking in situ observations of thermal, pickup, and energetic particles, while simultaneously remotely sensing the effects that these particles have in the outer heliosphere, by measuring Energetic Neutral Atoms (ENA) emissions produced by neutralized energetic ions when they charge exchange with interstellar neutral particles in that region. The IMAP-Ultra instrument (Ultra), one of the three ENA imagers on IMAP, measures the emission of the highest energy ENAs produced in the heliosheath and beyond. Ultra consists of two sensors with one sensor angled at 90° (Ultra90) and the other at 45° (Ultra45) from the spacecraft{\textquoteright}s spin axis. Ultra was designed and optimized to measure hydrogen (H) ENAs from 5 – 40 keV, but the sensors have been demonstrated to measure H from ∼3 – 300 keV. Additionally, Ultra{\textquoteright}s large ∼96° × 120° field of view (FoV) is capable of achieving angular resolutions ≤ 6° FWHM for ≥ 10 keV for H ENAs. Ultra provides high spatial resolution, full heliosphere maps, detecting changes in the spatial distribution of ENAs, on time scales sufficient to track both solar cycle as well as other major variations.",

keywords = "Energetic neutral atoms, Heliosheath, Heliosphere, IMAP, Interstellar medium, Termination shock",

author = "Matina Gkioulidou and Clark, \{G. B.\} and Mitchell, \{D. G.\} and Dupont, \{A. R.\} and Anderson, \{K. L.\} and S. Begley and M. Bzowski and Christian, \{E. R.\} and Cook, \{C. E.\} and Crew, \{A. B.\} and Cully, \{M. J.\} and R. DeMajistre and Diaz, \{T. J.\} and Drexler, \{R. J.\} and Dutton, \{N. T.\} and Gingrich, \{C. J.\} and Hayes, \{J. R.\} and Huber, \{C. M.\} and J. Hutcheson and Jaskulek, \{S. E.\} and P. Kollmann and LeBlanc, \{M. T.\} and J. Lees and McComas, \{D. J.\} and Nelson, \{K. S.\} and Parker, \{C. W.\} and Reisenfeld, \{D. B.\} and Rollend, \{E. A.\} and Schlemm, \{C. E.\} and Schwadron, \{N. A.\} and R. Verrill and J. Yen and J. Yin",

note = "Publisher Copyright: {\textcopyright} The Author(s) 2025.",

year = "2026",

month = jan,

doi = "10.1007/s11214-025-01256-5",

language = "English (US)",

volume = "222",

journal = "Space Science Reviews",

issn = "0038-6308",

publisher = "Springer Netherlands",

number = "1",

}

Gkioulidou, M, Clark, GB, Mitchell, DG, Dupont, AR, Anderson, KL, Begley, S, Bzowski, M, Christian, ER, Cook, CE, Crew, AB, Cully, MJ, DeMajistre, R, Diaz, TJ, Drexler, RJ, Dutton, NT, Gingrich, CJ, Hayes, JR, Huber, CM, Hutcheson, J, Jaskulek, SE, Kollmann, P, LeBlanc, MT, Lees, J, McComas, DJ, Nelson, KS, Parker, CW, Reisenfeld, DB, Rollend, EA, Schlemm, CE, Schwadron, NA, Verrill, R, Yen, J & Yin, J 2026, 'The IMAP-Ultra Energetic Neutral Atom (ENA) Imager', Space Science Reviews, vol. 222, no. 1, 4. https://doi.org/10.1007/s11214-025-01256-5

TY - JOUR

T1 - The IMAP-Ultra Energetic Neutral Atom (ENA) Imager

AU - Gkioulidou, Matina

AU - Clark, G. B.

AU - Mitchell, D. G.

AU - Dupont, A. R.

AU - Anderson, K. L.

AU - Begley, S.

AU - Bzowski, M.

AU - Christian, E. R.

AU - Cook, C. E.

AU - Crew, A. B.

AU - Cully, M. J.

AU - DeMajistre, R.

AU - Diaz, T. J.

AU - Drexler, R. J.

AU - Dutton, N. T.

AU - Gingrich, C. J.

AU - Hayes, J. R.

AU - Huber, C. M.

AU - Hutcheson, J.

AU - Jaskulek, S. E.

AU - Kollmann, P.

AU - LeBlanc, M. T.

AU - Lees, J.

AU - McComas, D. J.

AU - Nelson, K. S.

AU - Parker, C. W.

AU - Reisenfeld, D. B.

AU - Rollend, E. A.

AU - Schlemm, C. E.

AU - Schwadron, N. A.

AU - Verrill, R.

AU - Yen, J.

AU - Yin, J.

PY - 2026/1

Y1 - 2026/1

N2 - NASA’s Interstellar Mapping and Acceleration Probe (IMAP), a spinner spacecraft in orbit around L1, is taking in situ observations of thermal, pickup, and energetic particles, while simultaneously remotely sensing the effects that these particles have in the outer heliosphere, by measuring Energetic Neutral Atoms (ENA) emissions produced by neutralized energetic ions when they charge exchange with interstellar neutral particles in that region. The IMAP-Ultra instrument (Ultra), one of the three ENA imagers on IMAP, measures the emission of the highest energy ENAs produced in the heliosheath and beyond. Ultra consists of two sensors with one sensor angled at 90° (Ultra90) and the other at 45° (Ultra45) from the spacecraft’s spin axis. Ultra was designed and optimized to measure hydrogen (H) ENAs from 5 – 40 keV, but the sensors have been demonstrated to measure H from ∼3 – 300 keV. Additionally, Ultra’s large ∼96° × 120° field of view (FoV) is capable of achieving angular resolutions ≤ 6° FWHM for ≥ 10 keV for H ENAs. Ultra provides high spatial resolution, full heliosphere maps, detecting changes in the spatial distribution of ENAs, on time scales sufficient to track both solar cycle as well as other major variations.

AB - NASA’s Interstellar Mapping and Acceleration Probe (IMAP), a spinner spacecraft in orbit around L1, is taking in situ observations of thermal, pickup, and energetic particles, while simultaneously remotely sensing the effects that these particles have in the outer heliosphere, by measuring Energetic Neutral Atoms (ENA) emissions produced by neutralized energetic ions when they charge exchange with interstellar neutral particles in that region. The IMAP-Ultra instrument (Ultra), one of the three ENA imagers on IMAP, measures the emission of the highest energy ENAs produced in the heliosheath and beyond. Ultra consists of two sensors with one sensor angled at 90° (Ultra90) and the other at 45° (Ultra45) from the spacecraft’s spin axis. Ultra was designed and optimized to measure hydrogen (H) ENAs from 5 – 40 keV, but the sensors have been demonstrated to measure H from ∼3 – 300 keV. Additionally, Ultra’s large ∼96° × 120° field of view (FoV) is capable of achieving angular resolutions ≤ 6° FWHM for ≥ 10 keV for H ENAs. Ultra provides high spatial resolution, full heliosphere maps, detecting changes in the spatial distribution of ENAs, on time scales sufficient to track both solar cycle as well as other major variations.

KW - Energetic neutral atoms

KW - Heliosheath

KW - Heliosphere

KW - IMAP

KW - Interstellar medium

KW - Termination shock

UR - https://www.scopus.com/pages/publications/105025754355

UR - https://www.scopus.com/pages/publications/105025754355#tab=citedBy

U2 - 10.1007/s11214-025-01256-5

DO - 10.1007/s11214-025-01256-5

M3 - Review article

C2 - 41459002

AN - SCOPUS:105025754355

SN - 0038-6308

VL - 222

JO - Space Science Reviews

JF - Space Science Reviews

IS - 1

M1 - 4

ER -

The IMAP-Ultra Energetic Neutral Atom (ENA) Imager

Abstract

All Science Journal Classification (ASJC) codes

Keywords

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