Exploring the Outer Heliosphere Through ENA Observations from IMAP

D. B. Reisenfeld; F. Allegrini; E. R. Christian; G. B. Clark; M. A. Dayeh; P. Frisch; H. O. Funsten; A. Galli; M. Gkioulidou; F. Guo; Y. Huang; P. H. Janzen; T. K. Kim; G. I. Livadiotis; D. G. Mitchell; D. J. McComas; S. J. Noh; F. Rahmanifard; J. Richardson; N. A. Schwadron; J. Sokół; P. Swaczyna; J. R. Szalay; D. L. Turner; N. Walia; G. P. Zank; E. J. Zirnstein

doi:10.1007/s11214-025-01258-3

Exploring the Outer Heliosphere Through ENA Observations from IMAP

D. B. Reisenfeld
, F. Allegrini
, E. R. Christian
, G. B. Clark
, M. A. Dayeh
, P. Frisch
, H. O. Funsten
, A. Galli
, M. Gkioulidou
, F. Guo
, Y. Huang
, P. H. Janzen
, T. K. Kim
, G. I. Livadiotis
, D. G. Mitchell
, D. J. McComas
, S. J. Noh
, F. Rahmanifard
, J. Richardson
, N. A. Schwadron

J. Sokół, P. Swaczyna, J. R. Szalay, D. L. Turner, N. Walia, G. P. Zank, E. J. Zirnstein

Physics and Astronomy

Los Alamos National Laboratory
Southwest Research Institute
University of Texas at San Antonio
NASA Goddard Space Flight Center
Johns Hopkins University Applied Physics Laboratory
The University of Chicago
University of Bern
University of Alabama in Huntsville
Princeton University
University of New Hampshire
Massachusetts Institute of Technology
Space Research Centre, Polish Academy of Sciences

Research output: Contribution to journal › Article › peer-review

5 Scopus citations

Abstract

The Interstellar Mapping and Acceleration Probe (IMAP) mission is poised to revolutionize our understanding of two of the most central issues in heliophysics today: the nature of the interaction of the solar wind with the local interstellar medium (LISM), and the acceleration of energetic particles throughout the heliosphere. Here we focus on the anticipated contributions to this endeavor by measurement of hydrogen energetic neutral atoms (ENAs) that emanate from the solar wind–LISM interface region. ENA imaging allows us to remotely sense the structure and plasma characteristics of the heliosheath and the LISM just beyond the heliopause, and how these regions evolve in response to solar activity. These instruments, IMAP-Lo, IMAP-Hi, and IMAP-Ultra, cover energies from 10 eV to 300 keV with unprecedented angular resolution, energy resolution, and detection sensitivity. In this paper, we present the IMAP mission science specific to the study of the heliosphere/LISM interaction. We review what we have learned about the heliosphere interaction based on prior observations and theoretical studies. We then present the outstanding science questions that have consequently arisen and how IMAP plans to resolve them.

Original language	English
Article number	7
Journal	Space Science Reviews
Volume	222
Issue number	1
DOIs	https://doi.org/10.1007/s11214-025-01258-3
State	Published - Jan 2026

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Reisenfeld, D. B., Allegrini, F., Christian, E. R., Clark, G. B., Dayeh, M. A., Frisch, P., Funsten, H. O., Galli, A., Gkioulidou, M., Guo, F., Huang, Y., Janzen, P. H., Kim, T. K., Livadiotis, G. I., Mitchell, D. G., McComas, D. J., Noh, S. J., Rahmanifard, F., Richardson, J., ... Zirnstein, E. J. (2026). Exploring the Outer Heliosphere Through ENA Observations from IMAP. Space Science Reviews, 222(1), Article 7. https://doi.org/10.1007/s11214-025-01258-3

@article{65102a6fdf3b4d4c82598ccf04d4c6d1,

title = "Exploring the Outer Heliosphere Through ENA Observations from IMAP",

abstract = "The Interstellar Mapping and Acceleration Probe (IMAP) mission is poised to revolutionize our understanding of two of the most central issues in heliophysics today: the nature of the interaction of the solar wind with the local interstellar medium (LISM), and the acceleration of energetic particles throughout the heliosphere. Here we focus on the anticipated contributions to this endeavor by measurement of hydrogen energetic neutral atoms (ENAs) that emanate from the solar wind–LISM interface region. ENA imaging allows us to remotely sense the structure and plasma characteristics of the heliosheath and the LISM just beyond the heliopause, and how these regions evolve in response to solar activity. These instruments, IMAP-Lo, IMAP-Hi, and IMAP-Ultra, cover energies from 10 eV to 300 keV with unprecedented angular resolution, energy resolution, and detection sensitivity. In this paper, we present the IMAP mission science specific to the study of the heliosphere/LISM interaction. We review what we have learned about the heliosphere interaction based on prior observations and theoretical studies. We then present the outstanding science questions that have consequently arisen and how IMAP plans to resolve them.",

author = "Reisenfeld, \{D. B.\} and F. Allegrini and Christian, \{E. R.\} and Clark, \{G. B.\} and Dayeh, \{M. A.\} and P. Frisch and Funsten, \{H. O.\} and A. Galli and M. Gkioulidou and F. Guo and Y. Huang and Janzen, \{P. H.\} and Kim, \{T. K.\} and Livadiotis, \{G. I.\} and Mitchell, \{D. G.\} and McComas, \{D. J.\} and Noh, \{S. J.\} and F. Rahmanifard and J. Richardson and Schwadron, \{N. A.\} and J. Sok{\'o}{\l} and P. Swaczyna and Szalay, \{J. R.\} and Turner, \{D. L.\} and N. Walia and Zank, \{G. P.\} and Zirnstein, \{E. J.\}",

note = "Publisher Copyright: {\textcopyright} The Author(s) 2026.",

year = "2026",

month = jan,

doi = "10.1007/s11214-025-01258-3",

language = "English",

volume = "222",

journal = "Space Science Reviews",

issn = "0038-6308",

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Reisenfeld, DB, Allegrini, F, Christian, ER, Clark, GB, Dayeh, MA, Frisch, P, Funsten, HO, Galli, A, Gkioulidou, M, Guo, F, Huang, Y, Janzen, PH, Kim, TK, Livadiotis, GI, Mitchell, DG, McComas, DJ, Noh, SJ, Rahmanifard, F, Richardson, J, Schwadron, NA, Sokół, J, Swaczyna, P, Szalay, JR, Turner, DL, Walia, N, Zank, GP & Zirnstein, EJ 2026, 'Exploring the Outer Heliosphere Through ENA Observations from IMAP', Space Science Reviews, vol. 222, no. 1, 7. https://doi.org/10.1007/s11214-025-01258-3

TY - JOUR

T1 - Exploring the Outer Heliosphere Through ENA Observations from IMAP

AU - Reisenfeld, D. B.

AU - Allegrini, F.

AU - Christian, E. R.

AU - Clark, G. B.

AU - Dayeh, M. A.

AU - Frisch, P.

AU - Funsten, H. O.

AU - Galli, A.

AU - Gkioulidou, M.

AU - Guo, F.

AU - Huang, Y.

AU - Janzen, P. H.

AU - Kim, T. K.

AU - Livadiotis, G. I.

AU - Mitchell, D. G.

AU - McComas, D. J.

AU - Noh, S. J.

AU - Rahmanifard, F.

AU - Richardson, J.

AU - Schwadron, N. A.

AU - Sokół, J.

AU - Swaczyna, P.

AU - Szalay, J. R.

AU - Turner, D. L.

AU - Walia, N.

AU - Zank, G. P.

AU - Zirnstein, E. J.

PY - 2026/1

Y1 - 2026/1

N2 - The Interstellar Mapping and Acceleration Probe (IMAP) mission is poised to revolutionize our understanding of two of the most central issues in heliophysics today: the nature of the interaction of the solar wind with the local interstellar medium (LISM), and the acceleration of energetic particles throughout the heliosphere. Here we focus on the anticipated contributions to this endeavor by measurement of hydrogen energetic neutral atoms (ENAs) that emanate from the solar wind–LISM interface region. ENA imaging allows us to remotely sense the structure and plasma characteristics of the heliosheath and the LISM just beyond the heliopause, and how these regions evolve in response to solar activity. These instruments, IMAP-Lo, IMAP-Hi, and IMAP-Ultra, cover energies from 10 eV to 300 keV with unprecedented angular resolution, energy resolution, and detection sensitivity. In this paper, we present the IMAP mission science specific to the study of the heliosphere/LISM interaction. We review what we have learned about the heliosphere interaction based on prior observations and theoretical studies. We then present the outstanding science questions that have consequently arisen and how IMAP plans to resolve them.

AB - The Interstellar Mapping and Acceleration Probe (IMAP) mission is poised to revolutionize our understanding of two of the most central issues in heliophysics today: the nature of the interaction of the solar wind with the local interstellar medium (LISM), and the acceleration of energetic particles throughout the heliosphere. Here we focus on the anticipated contributions to this endeavor by measurement of hydrogen energetic neutral atoms (ENAs) that emanate from the solar wind–LISM interface region. ENA imaging allows us to remotely sense the structure and plasma characteristics of the heliosheath and the LISM just beyond the heliopause, and how these regions evolve in response to solar activity. These instruments, IMAP-Lo, IMAP-Hi, and IMAP-Ultra, cover energies from 10 eV to 300 keV with unprecedented angular resolution, energy resolution, and detection sensitivity. In this paper, we present the IMAP mission science specific to the study of the heliosphere/LISM interaction. We review what we have learned about the heliosphere interaction based on prior observations and theoretical studies. We then present the outstanding science questions that have consequently arisen and how IMAP plans to resolve them.

UR - https://www.scopus.com/pages/publications/105026933545

U2 - 10.1007/s11214-025-01258-3

DO - 10.1007/s11214-025-01258-3

M3 - Article

AN - SCOPUS:105026933545

SN - 0038-6308

VL - 222

JO - Space Science Reviews

JF - Space Science Reviews

IS - 1

M1 - 7

ER -

Exploring the Outer Heliosphere Through ENA Observations from IMAP

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