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Cold plasma: a previously hidden solar system particle population

Cold plasma: a previously hidden solar system particle population. Mats André and Chris Cully Swedish Institute of Space Physics, Uppsala. Cold plasma. Cold: thermal energy, and drift energy, less than a few eV. From the Terrestrial ionosphere, planets or moons.

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Cold plasma: a previously hidden solar system particle population

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  1. Cold plasma: a previously hidden solar system particle population Mats André and Chris Cully Swedish Institute of Space Physics, Uppsala

  2. Cold plasma • Cold: thermal energy, and drift energy, less than a few eV. • From the Terrestrial ionosphere, planets or moons. • Cold ions hard to detect on SC charged to a few Volts • The more we look for cold plasmas, the more we find…

  3. Cold plasma: The ionosphere Atmosphere + sunlight/precipitating particles Observations: • Groundbased: magnetometers (currents), radio/ionosonds (density), radars/incoherent scatter radars… • Low altitude SC (not much charged, but instr. threshold, SC velocity…)

  4. Cold flowing plasma: Wake behind a charged SC Tail lobes Density from SC potential (calibrated) Cluster Engwall et al., (2009)

  5. Cold plasma: Particle instrument vs wake detection Cluster SC 4 SC potential control (60 V => 7 V) km/s 50 H+ vZ -50 -50 50 vX km/s Particles (black) SC 4 Wake E (red) SC 3 +20 -20 07:40 08:20 UT Engwall et al., (2006)

  6. Outflowing cold plasma H+ outflow about 1026 ions/s Cluster Engwall et al. (2009)

  7. Oxygen ion heating and outflow (Cluster) • High altitude, high energy – likely to escape (ion detector) • 2×1025 /s (0.5 kg/s) 0+ • (Nilsson et al., 2010) • Path to the lobes, where cold ion outflow has been detected • (E-field instr.) • 1026 /s H+ • (Engwall et al., 2009)

  8. Cold plasma: Total vs hot density Just inside the magnetopause Total density from plasma frequency (WHISPER instrument) 2001-01-31 eV 1000 Cluster Sauvaud et al., 2001 10 10 cm-3 0.1 05:50 06:00 UT

  9. Magnetic reconnection, Cluster (magnetopause) 20 min Reconnection jet 10s 6000km 2 min

  10. Magnetic reconnection, Cluster (magnetopause) 30 s (1500 km) 4 s (200 km) • Cold (eV) ions at the magnetopause • Important for EN at edge of recon. jet (acceleration) EN André et al. (2010)

  11. Cold plasma: Recent results from the magnetopause Cluster SC 4, 2008 Total about 150 MP crossings Percent of crossings Red: high lat Blue: low lat Black: total 30 Cold ions, from wake E, within certain time inside MP 10 1 4 Time from MP (hours) Status report, to be continued…

  12. Cold plasma: Titan 0.1 100 Cassini Langmuir probe cm-3 0.1 10.0 Te (eV) 0.1 18:00 19:00 UT 2009-06-22 Edberg et al., 2011

  13. Cold plasma • How much cold plasma is there? • Cold plasma missing in estimates of ion outflow? • Cold plasma changes dynamics. • How can cold plasma stay cold? • Always stay tuned to find cold plasma when anywhere near a planet, moon or comet!

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