page_title: JEDI
hierarchical_section_title: JEDI
caption_attribution_description: Deutsch&#58; Bild von ultraviolettem Polarlicht auf Jupiter, aufgenommen mit dem Space Telescope Imaging Spectrograph (STIS) des Weltraumteleskops Hubble der NASA. • STScI-PRC00-38 Helle Streifen und Tupfen sind verursacht durch magnetischen Flussröhren, die Jupiter mit seinen größten Monden verbindet: Io: heller Streifen ganz links, Ganymed: heller Tupfer unterhalb der Bildmitte, Europa: Tupfer rechts dessen von GanymedEnglish&#58; This is a spectacular NASA Hubble Space Telescope close-up view of an electric-blue aurora that is eerily glowing one half billion miles away on the giant planet Jupiter. Auroras are curtains of light resulting from high-energy electrons racing along the planet's magnetic field into the upper atmosphere. The electrons excite atmospheric gases, causing them to glow. The image shows the main oval of the aurora, which is centered on the magnetic north pole, plus more diffuse emissions inside the polar cap. Though the aurora resembles the same phenomenon that crowns Earth's polar regions, the Hubble image shows unique emissions from the magnetic "footprints" of three of Jupiter's largest moons. (These points are reached by following Jupiter's magnetic field from each satellite down to the planet). Auroral footprints can be seen in this image from Io (along the left hand limb), Ganymede (near the center), and Europa (just below and to the right of Ganymede's auroral footprint). These emissions, produced by electric currents generated by the satellites, flow along Jupiter's magnetic field, bouncing in and out of the upper atmosphere. They are unlike anything seen on Earth. This ultraviolet image of Jupiter was taken with the Hubble Space Telescope Imaging Spectrograph (STIS) on November 26, 1998. In this ultraviolet view, the aurora stands out clearly, but Jupiter's cloud structure is masked by haze. This image was taken in UV light at 140 nm.
context_page_description: JEDI is an instrument on the Juno spacecraft orbiting planet Jupiter. JEDI coordinates with the several other space physics instruments on the Juno spacecraft to characterize and understand the space environment of Jupiter's polar regions, and specifically to understand the generation of Jupiter's powerful aurora. It is part of a suite of instruments to study the magnetosphere of Jupiter. JEDI consists of three identical detectors that use microchannel plates and foil layers to detect the energy, angle, and types of ion within a certain range. It can detect electrons between 40 and 500 keV, and hydrogen and oxygen from a few tens of keV to less than 1000 keV. JEDI uses radiation hardened Application Specific Integrated Circuits s. JEDI was turned on in January 2016 while still en route to Jupiter to also study interplanetary space. JEDI uses solid state detectors to measure the total energy of both the ions and the electrons. The MCP anodes and the SSD arrays are configured to determine the directions of arrivals of the incoming charged particles.
context_section_description: JEDI (Jupiter Energetic-particle Detector Instrument) is an instrument on the Juno spacecraft orbiting planet Jupiter. JEDI coordinates with the several other space physics instruments on the Juno spacecraft to characterize and understand the space environment of Jupiter's polar regions, and specifically to understand the generation of Jupiter's powerful aurora. It is part of a suite of instruments to study the magnetosphere of Jupiter. JEDI consists of three identical detectors that use microchannel plates and foil layers to detect the energy, angle, and types of ion within a certain range. It can detect electrons between 40 and 500 keV (Kilo electron-volts), and hydrogen and oxygen from a few tens of keV to less than 1000 keV (1 MeV). JEDI uses radiation hardened Application Specific Integrated Circuits (ASIC)s. JEDI was turned on in January 2016 while still en route to Jupiter to also study interplanetary space. JEDI uses solid state detectors (SSD's) to measure the total energy (E) of both the ions and the electrons. The MCP anodes and the SSD arrays are configured to determine the directions of arrivals of the incoming charged particles. The instruments also use fast triple coincidence and optimum shielding to suppress penetrating background radiation and incoming UV foreground.
  JEDI is designed to collect data on "energy, spectra, mass species (H, He, O, S), and angular distributions"; the plan is to study the energies and distribution of charged particles. It can detect them at between 30 keV and 1 GeV, whereas JADE, another instrument on the spacecraft, is designed to observe below 30 keV.  One of the concepts being studied is that energy from Jupiter's rotation is being converted into its atmosphere and magnetosphere.
  It is radiation hardened to collect in situ data on the planet's auroral magnetic field lines, the equatorial magnetosphere, and the polar ionosphere It was built by the Johns Hopkins University Applied Physics Laboratory (APL). One of the goals is to understand the aurora, and how particles are accelerated to such high speeds. One of the mysteries of Jupiter is that X-rays are emitted from the poles, but do not seem to come from the auroral ring.
  Each detector has a field of view of 120 degree by 12 degrees, and they are positioned to provide a 360 degree (a full circle) view of the sky along that axis. The Juno spacecraft travels very rapidly in the close vicinity of Jupiter (up to 50 km/s) and also spins very slowly (2 RPM).
  JEDI can detected particles from 30 to 1000 keV including:
  Electrons
  Proton (hydrogen) ions
  Helium ions
  Sulfur ions
  Oxygen ions
  Energetic neutral atoms (ENA's)
  In relation to other space missions, an instrument on the Earth-orbiting Van Allen Probes (launched 2012), called RBSPICE, is nearly identical to JEDI. This type of instrument is also similar to the PEPSSI instrument on New Horizons (Pluto/Kupiter probe).
  JEDI in combination with data from UVIS detected electrical potentials of 400,000 electron volts (400 keV), 20–30 times higher than Earth, driving charged particles into the polar regions of Jupiter.
  A scientific paper Juno observations of energetic charged particles over Jupiter's polar regions: Analysis of monodirectional and bidirectional electron beams  included results from a close pass over Jupiter's poles in August 2016 for electrons (25–800 keV) and protons (10–1500 keV). The paper analyzed electron angular beams in the auroral regions.
caption: Jupiter aurora; the bright spot at far left is the end of field line to Io; spots at bottom lead to Ganymede and Europa
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