<dB q >

2. Ring Current and Asymmetric Ring Current Bq BR Bq Bf Bt Btot <ddBq> <dBq> dBq <dBq> <ddBf> Gurnett, 2010 July 13, 2011 Magnetospheres of the Outer Planets - Boston, MA

3. Regions of Interest Sergis et al, 2010 We divided Saturn’s equatorial ring current into 3 radial regions based on their magnetic and plasma properties. July 13, 2011 Magnetospheres of the Outer Planets - Boston, MA

4. Determining the Rotation Rate w=799.2deg/day ccf=0.68 Better fit We chose a rotation rate and assigned the data a longitude (f) assuming that rotation rate. A sinusoidal fit of the form A sin (f + B) + C was performed on the organized data. The rate that gave the highest correlation coefficient was chosen. w=814 deg/day ccf=0.03 Poor fit July 13, 2011 Magnetospheres of the Outer Planets - Boston, MA

5. Introduction to Format of Results ccf=0.58 On the right, the data are organized by the rotation rate with the highest correlation coefficient and are plotted versus phase. The sinusoidal fit is drawn in black on top of the data, and the correlation coefficient is shown. The left panel plots the correlation coefficient of each fit between 790 deg/day and 820 deg/day, taken every 0.1 degree. The shaded gray region indicates 85% of the highest peak. The horizontal line is at 50% correlation coefficient, the cutoff for inclusion. The vertical lines indicate the best fits. July 13, 2011 Magnetospheres of the Outer Planets - Boston, MA

6. 2005-2006 Magnetic Perturbation Pressure ccf=0.58 ccf=0.68 6 < R < 9 9 < R < 12 ccf=0.68 12 < R < 15 July 13, 2011 Magnetospheres of the Outer Planets - Boston, MA

7. Total Ion Pressure (MIMI + CAPS) ccf=0.58 ccf=0.35 9 < R < 12 6 < R < 9 ccf=0.57 12 < R < 15 July 13, 2011 Magnetospheres of the Outer Planets - Boston, MA

8. CAPS Ion Effective Temperature [P/n] ccf=0.71 CAPS Ion Effective Temperature was only well organized in the region between 6 and 9 Saturn radii. Regions outside of 9 Rs had correlation coefficients below 0.5. July 13, 2011 Magnetospheres of the Outer Planets - Boston, MA

9. RPWS Electron Density – 3 to 5 Rs Gurnett, et al. have shown that the RPWS electron density data inside of 5 Rs tracks the SLS3 longitude. This is very close to the SLS4 South rotation rate. Outside of 5 Rs, there is no organization of the particle density in either the RPWS electron data or the CAPS Ion data. The correlation coefficient is less than 0.5. D A Gurnett et al. Science 2007;316:442-445 July 13, 2011 Magnetospheres of the Outer Planets - Boston, MA

10. Thermal Ion Perturbation Pressure Magnetic Perturbation Pressure ddBth (Persoon) RPWS Electron Density (Persoon) RPWS Electron Density (Gurnett) CAPS Ion Temperature Equatorial Rotation Rates 2005-2006 July 13, 2011 Magnetospheres of the Outer Planets - Boston, MA

11. Phase Relation Between Temperature and Pressure Density is not organized by the rotation rate of 800 deg/day. CAPS Ion Pressure appears to be in quadrature with the other parameters, but as the correlation coefficient with the fit is 0.38, a conclusive statement cannot be made. Magnetic Pressure and CAPS Ion Effective Temperature, organized at a rotation rate of 800 deg/day, are out of phase between 6 and 9 Rs. July 13, 2011 Magnetospheres of the Outer Planets - Boston, MA

12. Why might this be - CAM Model • There is a pressure peak in the range 5 to 10 RS and the peak rotates at the SKR period. • The Jia et al. model shows that inside of 5 Rs the density varies azimuthally (not illustrated), in accord with the electron density data described by Gurnett et al. data. • Outside of 5 Rs, the model predicts no azimuthal dependence on density, as we have found. • This implies that the azimuthal pressure variation arises through an azimuthal temperature variation. • Outside of ~10 Rs, there is no temperature variation, as seen in both the data and this simulation. Jia, Kivelson, and Gombosi, Submitted, 2011. July 13, 2011 Magnetospheres of the Outer Planets - Boston, MA

13. Why might this be - Vortex Model The inflow region would act like a giant suction hose which gathers and funnels hotter plasma of the middle magnetosphere towards the inner magnetosphere. At the mouth of the inflow region (8-12 Rs), the plasma is hot and tenuous. In the outflow region, the plasma is cold and dense forming a partial ring current. The plasma in the ring current region may not be corotational but the pressure peak would be. K. K. Khurana et al. PSG 2011 D. A. Gurnett et al. Science 2007;316:442-445 P. C. Brandt et al, GRL 2010 13 July 13, 2011 Magnetospheres of the Outer Planets - Boston, MA

14. d(Magnetic Pressure) 2009 284-365 805.9 806.5 805.7 Magnetospheres of the Outer Planets - Boston, MA July 13, 2011

15. d(Magnetic Pressure): Change Over Time 2005-2006 2009 S N S N S July 13, 2011 Magnetospheres of the Outer Planets - Boston, MA

16. Conclusions • Statistically significant rotation rates in ranges near SKR frequencies that organize the plasma parameters in late 2005 through early 2006 were not found. • Some rotation rates (preferred) stood out above the background by 15%. • In this “meta-analysis” perspective, the preferred frequencies cluster near the SLS4 North and South frequencies. • Magnetic pressure oscillates in late 2005 through early 2006 at the SLS4 South and the SLS4 North frequencies. • CAPS Ion Energy and the Magnetic Perturbation Pressure are in anti-phase in the equatorial plane between 6 and 9 Rs. • The 2009 magnetic pressure does not show two distinct peaks at the north and south SLS frequencies, but shows a broadened peak over the interval containing both. July 13, 2011 Magnetospheres of the Outer Planets - Boston, MA

17. Force Balance in Equatorial Ring Current Inertial Contribution Thermal Particle Pressure Magnetic Perturbation Pressure Curvature Force Radius Radius July 13, 2011 Magnetospheres of the Outer Planets - Boston, MA

18. Magnetic Pressure 2010 001-120 Ran out of steam. Will work on the rest tomorrow. Orbits are ~17-20 days long. Is big peak result of orbits? Magnetospheres of the Outer Planets - Boston, MA