The Juno Waves Investigation

Self Cite

Juno's first perijove science observations were carried out on 27 August 2016. The 90° orbit inclination and 4163 km periapsis altitude provide the first opportunity to explore Jupiter's polar magnetosphere. A radio and plasma wave instrument on Juno called Waves provided a new view of Jupiter's auroral radio emissions from near 10 kHz to ~30 MHz. This frequency range covers the classically named decametric, hectometric, and broadband kilometric radio emissions, and Juno observations showed much of this entire spectrum to consist of V‐shaped emissions in frequency‐time space with intensified vertices located very close to the electron cyclotron frequency. The proximity of the radio emissions to the cyclotron frequency along with loss cone features in the energetic electron distribution strongly suggests that Juno passed very close to, if not through, one or more of the cyclotron maser instability sources thought to be responsible for Jupiter's auroral radio emissions.

Section: Discussion and Summarymentioning

confidence: 99%

A new view of Jupiter's auroral radio spectrum

Kurth

Imai

Hospodarsky

et al. 2017

Self Cite

“…The data presented here were collected by the Juno spacecraft at a magnetic local time~0600 h, i.e., near the dawn terminator. Particle and field data were obtained from the magnetometer (MAG) instrument [Connerney et al, 2017], the plasma waves investigation (Waves) [Kurth et al, 2017], and the Jovian Auroral Distributions Experiment (JADE) [McComas et al, 2013].…”

Section: Discussionmentioning

confidence: 99%

“…The Waves investigation measured the magnetic field and electric field from 50 Hz to 20 kHz and 50 Hz to 40 MHz, respectively [Kurth et al, 2017]. In its survey mode of operation, used here, low-frequency (<21 kHz) power spectra were produced at a 2 s cadence.…”

Section: Geophysical Research Lettersmentioning

confidence: 99%

Juno observations of large‐scale compressions of Jupiter's dawnside magnetopause

Gershman

DiBraccio

Connerney

et al. 2017

We investigate the structure of Jupiter's dawnside magnetopause using observations obtained by particle and fields instrumentation on the Juno spacecraft. Characterization of Jupiter's magnetopause is critical for the understanding of mass and energy transport between the solar wind and the magnetosphere. We find an extended magnetopause boundary layer (MPBL) during a magnetopause crossing on 14 July 2016. This thick MPBL, in combination with a large magnetic field component normal to the magnetopause boundary, suggests that strong magnetospheric compression enhances mass transport across the magnetopause via magnetic reconnection. We further identify ~2 h increases in the total magnetospheric pressure adjacent to the magnetopause on 14 July 2016 and 1 August 2016. These large‐scale structures provide evidence of focused energy transport into the magnetosphere via magnetohydrodynamic structures.

“…The Waves (Kurth et al, 2017) and MWR (Janssen et al, 2017) instruments are two of nine instruments onboard Juno ) that operate independently. By chance, these instruments sometimes performed coincident observations that use the spacecraft internal clock to ensure a relative timing accuracy of 10 ms.…”

Section: Observationsmentioning

confidence: 99%

“…The Waves instrument (Kurth et al, 2017) consists of three receivers, one electric dipole antenna perpendicular to the spin z axis of the spacecraft, and one magnetic search coil sensor parallel to the z axis. By means of one Low Frequency Receiver and two redundant High Frequency Receivers, five different frequency bands are used to measure the electric fields of waves from 50 Hz to 41 MHz with the electric dipole antenna and the magnetic fields of waves from 50 Hz to 20 kHz with the magnetic search coil sensor.…”

Section: Observationsmentioning

confidence: 99%

Jupiter Lightning‐Induced Whistler and Sferic Events With Waves and MWR During Juno Perijoves

Imai

Santolı́k

Brown

et al. 2018

During the Juno perijove explorations from 27 August 2016 through 1 September 2017, strong electromagnetic impulses induced by Jupiter lightning were detected by the Microwave Radiometer (MWR) instrument in the form of 600‐MHz sferics and recorded by the Waves instrument in the form of Jovian low‐dispersion whistlers discovered in waveform snapshots below 20 kHz. We found 71 overlapping events including sferics, while Waves waveforms were available. Eleven of these also included whistler detections by Waves. By measuring the separation distances between the MWR boresight and the whistler exit point, we estimated the distance whistlers propagate below the ionosphere before exiting to the magnetosphere, called the coupling distance, to be typically one to several thousand of kilometers with a possibility of no subionospheric propagation, which gives a new constraint on the atmospheric whistler propagation.