Tom Stallard
Saturn’s
aurorae
University of
L
e
i
c
e
s
t
e
r
Sarah Badman, University of Lancaster
Ulyana Dyudina, Caltech
Denis Grodent, University of Liege
Jupiter
Earth
Bunce et al [2003] Persoon et al [2013]
Lamy et al., 2009
Radio aurora
Energetic particle
precipitation
H, H
2
H*, H
2
*
Energetic particle
precipitation
H, H
2
H*, H
2
*
H
2
= H
2
+
H
2
+
+
H
2
=
H
3
+
… … …
H
3
+
1 2 3
Energetic particle
precipitation
Lamy et al., 2013
Lyα
H
2
Visible aurora
Baβ
Based on Dyudina et al., submitted
H
2
Dyudina et al.
H
3
+
CH
4
Infrared aurora
Altitudinal extent
Morphology of the aurora
Badman et al., 2011
N>S
S>N
70
˚
60
˚
80
˚
Lamy et al., 2009Badman et al., 2006; 2012; Nichols et al., submitted
Talboys et al., 2011
UVIS
VIMS
ISS
Melin et al., 2011; submitted – see also Lamy et al., 2013
FUV EUV FUV+EUV
H
2
color ratio
Small scale structures
Spatial resolution ~200 km
0800
1000
1200
Dyudina et al., submitted; Grodent et al., WIP
Solar wind
interaction
(a)
Dayside reconnection
(a)
Tail reconnection
(a)
Unbalanced tail and dayside
reconnection e.g. large
compression-induced tail
reconnection
(b)
Rotating diffuse blob produced
by tail reconnection
After Badman et al. (2005), Cowley et al. (2005)
Stallard et al., 2012
Origin of these
small scale
auroral
features?
Complex Field-Aligned Current (FAC) structures
Bunce et al. [2010], Talboys et al. [2009,2011]
1-2° (lat) wide
FAC structures
Badman et al., 2012 Pryor, priv. comm.
Dusk spots non-conjugate
Origin of these
small scale
auroral
features?
Vortices triggered by K-H instabilities
Masters et al. [2010], Fukazawa et al. [2009],Walker et al. [2011], Delamere et al. [2011]
FAC associated
with dΩ
/// dt
> 0.55 R
SWilson et al. [2012]:
Meredith et al., 2013
Dyudina et al., submitted
Stallard et al., 2008
Magnetospheric
plasma
Mitchell et al., 2009
Radioti et al., 2012
Cassini/UVIS
UV aurora related to electrons injections 1) pitch angle diffusion + electron scattering and 2) FACs driven by ∇p along boundaries of hot plasma cloud (ENA)Cassini/INCA
variable color scale
Cassini/UVIS 2008_240_05_46 South Pole
Schippers et al., 2012 Grodent et al. WIP
Enceladus footprint
Pryor et al., 2011
O’Donoghue et al., 2013
Periodic
One-hour period oscillations
Nichols et al., submitted Nichols et al., 2010
Badman et al., 2012 Stallard
