University:
Boston University
Course:
CAS PY 105 | Physics 1
Academic year:

2020
Views:

475

Pages:

22
Author:

Alisson Short

Dust and low temperature plasma of Saturn Outline • • • • Plasma source of Saturn’s magnetosphere Moon Enceladus and its plume observations Cold and dusty plasma observation by RPWS/LP Dusty plasma effect in the magnetosphere (suggestion) Plasma in Saturn’s magnetosphere Solar wind Cold Plasma Hot Plasma Ring from Kellet et al. (2009) Plasma in Saturn’s magnetosphere Plasma are accumulated until 5RS and centrifugally transported outward. ← Persoon et al. (2005) Persoon et al. (2009) ↓ Water rich plasma disk center Enceladus E-ring Enceladus plume detected by MAG • Bx shows the expected Alfvén wing of the southern plume. • By are rather difficult to interpret. Dougherty et al. (2006) Cassini Enceladus flybys E01 E02 E03 E04 E05 E06 2005/03/09 2005/07/14 2008/03/12 2008/08/11 2008/10/09 2008/10/31 500 172 52 50 25 197 E07 E08 E09 E10 2009/11/02 99 2009/11/21 1603 2010/04/28 99 2010/05/18 198 Enceladus plume/E ring observations • Plume detection by B perturbation: Dougherty et al. (2006) • Neutral observations: Waite et al. (2006), Water vapor in the plume • Dust observations: Kempf et al. (2010), CDA sub-µm sized dust Kurth et al. (2006), RPWS sub-µm sized dust Jones et al. (2009), Coates et al. (2010), ≤ nano meter sized dust • Dust and Plasma observations: Tokar et al. (2009), high energy ions slowing down Farrell et al. (2010), CAPS & RPWS comparison and suggesting dust pick up nano meter sized dust grains negative grains negative ions positive grains Singly (negative and positive) charged nano meter (up to 2 nm) sized grains are detected. Jones et al. (2009) Slowing down of co-rotating ion co-rotating ion slowing down new cold plume plasma Tokar et al. (2009) Slowing down of co-rotating ion co-rotating ion slowing down new cold plume plasma Tokar et al. (2009) very cold ion also here? Farrell et al. (2009, 2010) RPWS Electron dropout coincideRPWS with the & CAPS RPWS dust impact electron dropout dust hit impact nano meter grains Farrell et al. (2009, 2010) RPWS & CAPS electron dropout corotating ion slowing down dust hit impact E03 µm sized dust impact Electron current Ion current Fuh E03 µm sized dust impact ~±20RE Electron current Ion current E03 µm sized dust impact ~±20RE Electron current Ion current Spurious signal of dust E03 µm sized dust impact ~±20RE Electron current Ion current Spurious signal of dust Ne decreases, but no Ni decreasing. NO WAKE! E3 Large plasma densities: Ne > 103 [cm-3] Ni > 104 [cm-3] lots of plasma! E3 Large plasma densities: Ne > 103 [cm-3] Ni > 104 [cm-3] Ni >> Ne E3 Ne/Ni ≈ 0.01 E3 Ne/Ni << 1 not only in the plume E3 Ne drop out ‘ideal wake’ region NO Ni WAKE Surrounding plasma is not co-rotating but moving with Enceladus. E3 NO Ni WAKE ‘ideal wake’ region Vi < Vco-rotation not only in plume, all the time!