The Particle Environment Package (PEP) on board The Jupiter Icy Moon Explorer (JUICE) Stas Barabash1 (PI), Peter Wurz2 (Co-PI), Pontus C. Brandt3 (US Lead), C. P. Paranicas3, D. G. Mitchell3, G. Ho3, J. Westlake3, B. H. Mauk3, D. Haggerty3, K. Khurana4, X. Jia5, C. Paty6, N. Krupp7, M. Fraenz7, E. Kallio8, K. Szego9, N. Andre10, G. Jones11 + the rest of the PEP Team 1The Swedish Institute of Space Physics, Kiruna, Sweden. 2University of Bern, Switzerland. 3The Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USA. 4UCLA, CA, USA. 5University of Michigan, MI, USA. 6Georgia Tech, GA, USA. 7Max-Planck Institute, Lindau, Germany. 8Finnish Meteorological Institute, Helsinki, Finland. 9Wigner Institute, Budapest, Hungary. 10IRAP, Toulouse, France. 11MSSL, United Kingdom.

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PEP Science Target: A Mini-solar System and Astrophysical Object

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Magnetospheres

PEP Overview

JDC Jovian plasma Dynamics and Composition The Swedish Institute of Space Physics, Sweden.

JNA Jovian Neutral Atoms The Swedish Institute of Space Physics, Sweden.

JEI Jovian Electrons and Ions Max-Planck Institute, Germany.

NIM Neutral and Ion Mass spectrometer University of Bern, Switzerland.

Zenith Unit (ZU) Nadir Unit (NU)

Approved for Public Release 4

JoEE Jovian Energetic Electrons

APL, USA.

JENI Jovian Energetic Neutrals and Ions APL, USA.

PEP Science Questions and Objectives

PEP Science Question 1: How does the corotating magnetosphere of Jupiter interact with the complex and diverse environment of Ganymede?

PEP Science Question 2: How does the rapidly rotating magnetosphere of Jupiter interact with the seemingly inert Callisto?

PEP Science Question 3: What are the governing mechanisms and their global impacts of release of material into the Jovian magnetosphere from seemingly inert Europa and active Io?

PEP Science Question 4: How do internal and solar wind drivers cause such energetic, time variable and multi-scale phenomena in the steadily rotating giant magnetosphere of Jupiter?

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PEP Team

US Manager S.E. Jaskulek (APL)

IRF Manager H. Andersson (IRF)

IRF Lead S. Barabash (IRF)

Electrical

UBe Lead P. Wurz (UBe)

Mechanical , unit I&T

UBe Manager K. Seiferlin (UBe)

PEP PI S. Barabash (IRF)

PEP Co-PI P. Wurz (UBe)

PA Manager TBD (UBe)

Lead Funding Agency SNSB, Sweden

ESA National Funding Agencies

JoEE Lead C.P. Paranicas (APL)

Dpt: G. Ho

JENI Lead D.G. Mitchell (APL)

Dpt: J. Westlake

DPU E. Kallio (FMI)

NIM Lead P. Wurz (UBe)

JNA Lead M. Wieser (IRF)

JDC Lead M. Wieser (IRF)

JEI Lead M. Fränz (MPS)

Radiation Manager S. Karlsson (IRF)

US Lead P.C. Brandt (APL)

Dpt: C.P. Paranicas (APL)

Sensors & Subsystems

Power / EGSE K. Szegõ (WRCP)

PEP Manager H. Andersson (IRF)

Dpt: M.Emanuelsson (IRF)

Scientific Co-Is M. Holmström (IRF) Y. Futaana (IRF) G. Stenberg (IRF) H. Nilsson (IRF) A. Ericsson (IRF) A. Vorburger (UBe) N. Krupp (MPS) E. Roussos (MPS) M. Grande (UA) H. Lammer (IWF) T. Zhang(IWF) T. Sarris (DUTh) B. Heber (CAU) S. M. Krimigis (Athens) D. Haggerty (APL) K. K. Khurana (UCLA) B. Mauk (APL) C. Paty (GaTech) X. Jia (UM) G. Jones (MSSL) N. Andre (IRAP)

US Radiation Manager J. Westlake (APL)

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Science Highlights: Ganymede Interior

Disentangling the Induction Response of an Internal Ocean

Schematics adapted from Khurana et al. (2002) showing (a) magnetic field lines of the dipolar response (Bind (t)) of a spherical perfect conductor (in which induced eddy currents are flowing) to a uniform time-varying external field (Bprim(t)), (b) magnetic field lines of the resulting total field (Bprim(t)+ Bind (t)), which are tangent to the surface of the sphere and do not penetrate into the conductor.

Jovian Dynamics and Composition (JDC) The Swedish Institute of Space Physics, Kiruna Plasma ions and electrons 1 eV – 41 keV, ∆E/E=12% M/∆M=30 Hemispheric, 5.5˚x19.5˚ resolution

Jovian Electrons and Ions (JEI) Max-Planck Institute, Lindau Plasma electrons and ions ~1 eV – 50 keV, ∆E/E=4.9% Hemispheric, 20˚x10˚ resolution

Science Highlights: Ganymede Interior

Disentangling the Induction Response of an Internal Ocean

The dynamic plasma flow of the Jovian magnetosphere shapes and distorts the draped field around the icy moons. In a 500 km Ganymede orbit, the expected induction signal is 10’s of nT. The field perturbations from the plasma interactions are expected to be of the same order or more. Measurements of the plasma flows and densities are therefore analyzed together with the field measurements to isolate the pure induction signal.

Jovian Dynamics and Composition (JDC) The Swedish Institute of Space Physics, Kiruna Plasma ions and electrons 1 eV – 41 keV, ∆E/E=12% M/∆M=30 Hemispheric, 5.5˚x19.5˚ resolution

Jovian Electrons and Ions (JEI) Max-Planck Institute, Lindau Plasma electrons and ions ~1 eV – 50 keV, ∆E/E=4.9% Hemispheric, 20˚x10˚ resolution

Science Highlights: Ganymede Surface Interactions

Remotely Imaging the Particle Precipitation Patterns on Ganymede

Chandrayaan observations of the Lunar surface have revealed that ions impacting the surface back scatters as neutrals with 10-20% efficiency. This has enabled a technique to remotely image where ions impact the surface.

Jovian Neutral Atoms (JNA) The Swedish Institute of Space Physics, Kiruna Low-energy ENA 10 eV – 3 keV (H) 7˚x25˚ resolution

JNA images low-energy neutrals by converting them to ions that subsequently are guided through a light-trap and subjected to TOF analysis.

Science Highlights: Io Plasma Torus

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Low-energy ENA (10-100’s eV) Remote Imaging of the Io Plasma Torus

Ions in the Io plasma torus charge exchange with the neutral gas and produce a “neutral spray” emanating around its tangential direction. Detection of these low-energy ENAs enables remote imaging of the Io torus ion distribution and temporal changes (Futaana et al., PSS, in review, 2014).

JNA images low-energy neutrals by converting them to ions that subsequently are guided through a light-trap and subjected to TOF analysis.

Jovian Neutral Atoms (JNA) The Swedish Institute of Space Physics, Kiruna Low-energy ENA 10 eV – 3 keV (H) 7˚x25˚ resolution

Science Highlights: Europa Sources

NIM’s prime targets are the icy moon exospheres and its relation to surface (and sub-surface) release. NIM resolves species and isotopes with high resolution to also help understand mineralogical composition of the surface. NIM’s ability to resolve mineral mixing ratios down to 1% provides IR measurements constraints on surface composition.

First-Ever In-situ Sampling of the Exospheres of the Jovian Moons

NIM is a ToF mass spectrometer using an ion mirror (reflectron) (Wurz et al., 2012). Neutrals are collected and ionized and then accelerated in the TOF ion mirror that separates mass.

Neutral Ions and Neutrals (NIM) University of Bern, Switzerland Thermal neutrals and ions (< 5 eV) Mass range: 1-1000 amu M/∆M=1100 Sensitivity: 2 cm-3 (~10-16 mbar)

Science Highlights: Europa Sources

Expected densities in Europa’s exosphere at the dayside. White and light brown areas indicate the range of possible NIM measurements during Europa flyby. Left boundary is given by the 400 km flyby altitude, lower boundary by the NIM sensitivity. Light brown area corresponds to radiation background.

Neutral Ions and Neutrals (NIM) University of Bern, Switzerland Thermal neutrals and ions (< 5 eV) Mass range: 1-1000 amu M/∆M=1100 Sensitivity: 2 cm-3 (~10-16 mbar)

NIM is a ToF mass spectrometer using an ion mirror (reflectron) (Wurz et al., 2012). Neutrals are collected and ionized and then accelerated in the TOF ion mirror that separates mass.

Science Highlights: Variability of Europa’s Gas Cloud

Jovian Energetic Neutrals and Ions (JENI) JHU/APL, Laurel, MD ENA and ions ~0.5 – 300 keV (ENA), 5 MeV (ions) ∆E/E=14% 90˚x120˚, 2˚ resolution (>10 keV H)

Imaging the Global Variations of Europa’s Neutral Gas Cloud

The neutral gas torus of Europa is JENI’s brightest object in the Jovian system. JENI will therefore provide a possibility to monitor the variability of Europa’s gas cloud to constrain surface release processes and their variations remotely.

JENI is a combined ENA camera and ion imaging spectrometer. A foil-based TOF system provides triple coincidences to operate in Jupiter’s harsh environment.

1st Generation: Cassini/INCA

2nd Generation: JUICE/JENI

Science Highlights:The Giant Particle Accelerator

Combining remote global ENA imaging of large-scale injections with high-resolution in-situ measurements has been a very successful technique used by Cassini at Saturn to fully probe the global behavior and detailed physical heating and transport mechanism.

Jovian Energetic Neutrals and Ions (JENI) JHU/APL, Laurel, MD ENA and ions ~0.5 – 300 keV (ENA), 5 MeV (ions) ∆E/E=14% 90˚x120˚, 2˚ resolution (>10 keV H)

JENI is a combined ENA camera and ion imaging spectrometer. A foil-based TOF system provides triple coincidences to operate in Jupiter’s harsh environment.

1st Generation: Cassini/INCA

2nd Generation: JUICE/JENI

Science Highlights:The Giant Particle Accelerator

Jovian Energetic Electrons (JoEE) JHU/APL, Laurel, MD Energetic electrons 25 keV – 1 MeV, ∆E/E≤20% 12˚x180˚, 12˚x22˚ resolution ∆t = 0.3 s

Probing The Giant Particle Accelerator

JoEE measures an energy spectrum near-simultaneously in eight different directions using a self-closing magnets to separate electrons of different energies on to SSD pixels for spatial coincidences.

JoEE obtains pitch-angle distributions as a function of energy at sub-second resolution. This is key to probe the acceleration mechanisms that makes the Jovian magnetosphere the Giant Particle Accelerator of the solar system.

Cassini Observations Consistent with Asymmetric Europa Torus

Cassini/INCA Observation

Cassini/INCA Simulation

Sun

Cassini at 144 RJ

Cassini Observations Consistent with Asymmetric Europa Torus

Cassini/INCA Observation

Deconvolved Image (no Point Spread)

Sun

Cassini at 144 RJ

PEP Milestones

pontus.brandt@jhuapl.edu 18

Milestone Date Mission Adoption Nov 2014

IPDR July 2016

ICDR Aug 2017

Instrument Flight Model Delivery Aug 2018

Launch June 2022

JOI Jan 2030

End of Nominal Mission June 2033