Auroral Physics at Jupiter:
Radio and Plasma Wave Observations by Juno
W. S. Kurth,
G. B. Hospodarsky
University of Iowa
Presented at LASP, 7 March 2016
JunoScienceObjec-ves
Origin
DetermineO/Hra.o(waterabundance)andconstrain
coremasstodecideamongalterna.vetheoriesoforigin.
Interior
UnderstandJupiter'sinteriorstructureanddynamical
proper.esbymappingitsgravita.onalandmagne.c
fields
Atmosphere
Mapvaria.onsinatmosphericcomposi.on,
temperature,cloudopacityanddynamicstodepths
greaterthan100barsatallla.tudes.
Magnetosphere
Characterizeandexplorethethree-dimensionalstructure
ofJupiter'spolarmagnetosphereandauroras.
JunoPayload
X and Ka Band Gravity Science (JPL/ASI)
Six Microwave Radiometers— MWR (JPL)
Magnetometer— MAG (GSFC/DTU)
Camera - JunoCam (Malin)
Three Energetic Particle Detectors—JEDI (APL)
Four Jovian Auroral Distributions — JADE (SwRI)
Waves (U of Iowa)
UV Spectrometer— UVS (SwRI)
IR Camera/Spec –JIRAM (ASI)
PolarMagnetosphereExplora-on
Location is Key: Juno passes directly
through auroral field lines.
A suite of instruments is used to
understand the physics:
JADE, JEDI, MAG, Waves, JIRAM, UVS
OutstandingQues-ons:PolarMagnetosphere
•  Whatstructureofthepolarmagnetosphere?Howdoesit
comparetoEarth’s?
•  Whereandhowareauroralpar.clesaccelerated?
•  Whereandhowareauroralradioemissionsgenerated?
•  Whatcausesthetransientpolaraurora?
•  Whatisthetopologyofthepolarmagne.cfield?Howmuch
connectstothesolarwindandhowvariableisthis?
•  Howdointernalmagnetosphericdynamicsandsolarwind
variabilityaffectthemainaurora?
•  Howdoesthepolarmagnetospherecoupletothedistant
magnetotail?
ARerBagenaletal.,SpaceSci.Rev.,2014.
OtherOutstandingQues-ons
•  Howareradia.onbeltpar.clesacceleratedandwhat
processesdrivethestructureanddynamicsoftheradia.on
belts?
•  Howisthemagnetospherecoupledtothesolarwind?How
muchmassandmomentumaretransferred?
•  Whatroledoesthesolarwindplayinmagnetospheric
dynamicsandhowdeepdoesitsinfluencepenetrate?
ARerBagenaletal.,SpaceSci.Rev.,2014.
Junowillenable
comparisonswith
terrestrialauroral
physics
Paschmannetal.(2002)
JunoMissionPlan
Baselinemission:
32polarorbits,12degreenet
Perijove~5000km
14dayperiod
Spinning,solarpowered
OrbitalTrajectory
JunoWavesScienceObjec-ves
•  Waves primary objectives:
–  Explore radio and plasma waves
in Jupiter’s polar magnetosphere
–  Examine the role of plasma waves
in the auroral acceleration region
–  Identify source regions for
Jupiter’s primary radio emissions
and observe these in situ
•  Additionally, Waves will:
–  Observe the structure and
dynamics of the plasmasheet
–  Monitor radio emissions as a
proxy for magnetospheric
dynamics
–  Measure dust impacts between
the ring system and the
atmosphere
JunoWavesOverview
ElectricAntenna
Preamps&
Electronics
InstrumentCharacteris-cs
SearchCoil
SpectralCoverage
50Hz–20kHzMagne.c
SpectralCoverage
50Hz–40MHzElectric
SpectralResolu.on
~20Channels/decade
PeriapsisModeCadence 1spectrum/s
LFandMFBurstModes WaveformCapturesinallbandsto150
kHztriggeredonboard
HFBurstModes
Abilitytoselecta1-MHzbandincludingfce
PrimeWavesTargets
Ergunetal.
A-G00-143
Voyager 1, March 4 - 7, Days 63 - 65, 1979
R (RJ)
30
Day
SCET
25
63
00
20
15
10
64
00
12
5 5
12
10
15
20
65
00
25
12
30
66
00
-4
Log Electric Field (Vrms/m)
Log Frequency (Hz)
4
fCE
3
2
CouplingtheMiddle
MagnetospheretotheAurora
-5
A-G00-88
Voyager 1
March 6, Day 65, 1979
Start SCET 0345:32
8
-6
BEN (BSKG)
10.
6
1
1
2
3 4
5
6
7 8
4
1.0
2
0.1
0
Time
:40
:50
0346:00
:10
:20
1
0
-1
0
10
R = 16.0 RJ
Barbosaetal.,1981
20
30
Time (ms)
λm = -7.7E
40
λII I = 7E
50
AuroralRadioEmissions
A-G01-165-4
Cassini RPWS
September 18, Day 262, 2000
6
10.0
dB Above Background
Frequency (MHz)
Io-Controlled
Decametric
Radiation
Hectometric
Radiation
1.0
Kilometric Radiation
4
2
0.1
0
UT
0000
R (RJ ) 1353
8III (E)
35
NIo (E) 67
Zarkaetal.,2004.
0200
1352
108
84
0400
1351
180
101
0600
1350
253
118
0800
1349
325
135
1000
1348
38
152
AuroralRadioEmissionSource
Saturn Kilometric Radiation
04:00
-2
-4
5
10
2
4
6
D (R S)
fce
fpe
3
10
-7
10
-8
8 10
V2m-2Hz-1
Frequency (Hz)
08:00
L = 25
L=30
-6
0
4
10
-6
10
0
Z (R S)
6
10
A-G10-001
2
Cassini Orbit 89
October 17, Day 291, 2008
Narrowband Z-mode
Emissions
-9
10
-10
10
-11
10
Auroral Hiss
2
10
1
10
04:00
RS
3.95
Inv. Lat 60.68
Lat -13.34
LT 22.77
L
4.17
-12
10
-13
10
06:00
4.21
71.24
-39.03
23.39
6.97
08:00
4.75
76.42
-59.25
0.37
18.15
10:00
5.45
82.29
-71.76
2.33
55.56
12:00
6.21
83.73
-74.20
5.32
83.86
SolarWind/MagnetosphericInterac-ons
Observa-onPlanning
PJ 5
2016-11-30T15:52:00.001Z
2016-328 16:23 to 2016-356 14:16
20.
10.
0.
-10.
Apoapsis
Intermediate
Periapsis
Burst
-20.
0.
10.
20.
30.
40.
50.
PlasmaWavesinEarth’sRadia-onBelts
TerrestrialLightningWhistlers
InterplanetaryShockAssociatedwith
X4.9flareon2/25/2014
•
•
•
•
•
Class X4.9 flare occurred early on 25 February
Associated with coronal mass ejection
Juno/Waves observed type III solar radio
emission
Disturbance propagated to Juno as an
interplanetary shock shown here
Upstream plasma oscillations caught in Waves
burst mode.
JunoDustImpact
Juno Waves December 2, Day 336, 2011
6×10
20:38 SCET
4
Voltage (dn)
4
5×10
4
4×10
4
3×10
~ 200 mV
4
2×10
4
1×10
0.
0.
20.
40.
60.
Time (ms)
80.
100.
120.
Earth-basedSuppor-ngObserva-ons
•  GlennOrtonisresponsiblefororganizingEarth-basedobserva.onsin
supportoftheJunomission
–  Amateurs
–  Professionals
•  Specificallyforauroralphysics,professionalsupportisexpectedfrom:
–  HSTUV(e.g.NicholsCycle23coincidingwithJuno’sorbitinser.on)
–  IRTFH3+
–  GiantTelescopes:COMICS,VISIR,CanariCam(Mid-IR)
•  PhilipZarkawasaskedtocoordinateground-baseddecametricradio
observa.onsunderanad-hocgroupnamed“JunoGroundRadio”:
–  NançayDecameterArray(France)
–  LOFAR(variousEuropeanloca.ons)
–  UTR-2,URAN1-4(Ukraine)
–  LWA,LWA1(USA)
–  TohokuU.,FukuiInst.Tech.,U.Elect.&Comm.,KochiU.(Japan)
–  Others
Summary
•  Theexplora.onofthepolarmagnetosphereisabasic
objec.veofJuno.
•  Thepolarorbitwithverylowperiapsisisidealtosurveythe
expectedauroralaccelera.onregion.
•  Junohasawell-balancedpayloadallowingacomprehensive
examina.onofauroralprocessesatJupiter
•  JunoWavesinves.ga.onshouldallowcomparisonswiththe
terrestrialauroralsitua.on,therebyadvancingour
understandingofJupiter’spolarmagnetosphere.
•  ArrivalonJuly4,2016!
UVSandJIRAMobserveauroralemissionson
approach&departure
Insituinstrumentsmeasurepar-cles&fieldsover
polesandinplasmadisk
TheauroraisthesignatureofJupiter’s
a\empttospinupitsmagnetosphere
Downward ???
?
Upward ~ OK
?
Hill; Cowley et al.,
25