1. Multipoint observations of nightside auroral activity: the Cascades2 sounding rocket mission K A Lynch, Dartmouth College 2009 Fall AGU SM53D-05 Dartmouth College Cornell UniversityNASA Wallops Flight Facility University of New HampshireNSROC University of Alaska FairbanksPFISR KTH-StockholmPoker Flat Research Range SRI SSL/UCB

2. Outline Cascades2 mission and goals March 2009 PFRR nightside event Three science topics – PBI case study (Themis, PFISR, cameras, in situ observations) – Measurement of DCE shear frequencies – Deconvolving a tall-ray event Summary and ongoing efforts

3. Science objectives and questions (1) Does dynamic aurora move with respect to the background ionosphere? How much? Does it matter? Proper motion and evolution of arc structures… (2) What is the spatial as compared to temporal variation of auroral parameters like B and E? What does this mean for theories of energy transfer? Quantifying shears… (3) Alfven waves carry disturbances and changes down to and through the auroral zone, giving us structured and dancing aurora. They are pretty: do they matter? Are these structures significant for magnetosphere/ionosphere coupling? Do direct observations of these motions validate theories and models? Deconvolving a tall-ray event…

4. BoBo PFRR PFISR Toolik Kaktovic E and B along B o e- across B o Fast e- down B o Image down B o Ground cameras Radar GPS position and timing C2 array:

5. Event: 20 March 2009 11:11:11UT apogee Near local magnetic midnight 564 km apogee Repeating PBI event

6. PBI case study First two, unaccelerated (or minimally accelerated) Maxwellians Different from “typical” inverted-V arcs, but discrete 3 rd, wave accelerated, field-aligned

7. Shear Frequencies TimeMax North Difference Assuming Perp Shear Assuming Parallel Shear 602.2-602.5.052 V/m3.714 Hz.186 Hz 602.5-602.8.054 V/m5.5 Hz.19 Hz 602.8-603.3.148 V/m10.57 Hz.528 Hz TimeMax East Difference Assuming Perp Shear Assuming Parallel Shear 602.2-602.5.077 V/m5.5 Hz.275 Hz 602.5-602.8.093 V/m6.64 Hz.332 Hz 602.8-603.3.065 V/m4.57 Hz.232 Hz

9. Tall rays

10. Array size: 4-6 km along B ~0.5 km across B Structure: footpoint 100-200 km altitude 2 km wide/13 km/sec = 0.15sec

11. Other ongoing Magnetometer deconvolution Ion motion up and down field line Further development of onboard camera Plasma density measurements Stereo camera imaging Multiple-point measurements separating d/dx from d/dt….3 payloads, 4 payloads, 5 payloads, …10?

12. www.dartmouth.edu/~aurora