Transient Phenomena at the Magnetopause and Bow Shock and Their Ground Signatures Christina Chu University of Alaska Fairbanks Geophysical Institute -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- GEM Student Tutorial 12 June 2012 Logo: gi Picture: M. Jason Ahrns Picture courtesy J. Ahrns

What Kinds of Phenomena? Hot Flow Anomalies Foreshock Bubbles, Cavities, Cavitons, Compressional Boundaries Density Holes Magnetopause Reconnection Plasma Entry to Mantle Flux Transfer Events Topics in this powerpoint will be discussed in the GEM focus group “Transient Phenomena at the Magnetopause and Bow Shock and Their Ground Signatures” Why should we care? Disruptions can be carried through bow shock causing changes in magnetosheath which can lead to surface waves in the magnetopause Christina Chu University of Alaska Fairbanks GEM 2012 Student Tutorial – Transient Phenomena at the Magnetopause and Bow Shock and Their Ground Signatures

Hot Flow Anomalies (HFAs) Occur at the bow shock Characterized by Flow deflection Temperature increase Schwartz et al. [1985] Hot diamagnetic cavity=active current sheet=HFA HFA Simulation from N. Omidi Christina Chu University of Alaska Fairbanks GEM 2012 Student Tutorial – Transient Phenomena at the Magnetopause and Bow Shock and Their Ground Signatures

Hot Flow Anomaly Formation Theory Discontinuity in solar wind hits bow shock Coupling between incoming solar wind beam and reflected ion beam = heating HFA expands causing the signatures seen Ni B vx Ti vy vz and Image: http://www.google.com/imgres?um=1&hl=en&client=firefox-a&rls=org.mozilla:en-US:official&channel=fflb&authuser=0&biw=1318&bih=873&tbm=isch&tbnid=Brx3boFHZT6UqM:&imgrefurl=http://roma2.rm.ingv.it/en/themes/22/magnetic_pulsations/36/upstream_waves&docid=O-j_H-der4uNIM&imgurl=http://roma2.rm.ingv.it/userfiles/image/tematiche/PulsazioniGeomagnetiche/onde_fig1_en.jpg&w=505&h=478&ei=e1fXT9mlD8GQ2gXSxJy7Dw&zoom=1&iact=hc&vpx=527&vpy=487&dur=1265&hovh=218&hovw=231&tx=104&ty=131&sig=101697176962587057094&page=1&tbnh=167&tbnw=173&start=0&ndsp=22&ved=1t:429,r:13,s:0,i:114 http://www.google.com/imgres?um=1&hl=en&client=firefox-a&rls=org.mozilla:en-US:official&channel=fflb&authuser=0&biw=1318&bih=873&tbm=isch&tbnid=-e4L-US7A-G0TM:&imgrefurl=http://www3.imperial.ac.uk/portal/page%3F_pageid%3D488,31916042%26_dad%3Dportallive%26_schema%3DPORTALLIVE&docid=Zsas7ha8WS6EuM&imgurl=http://www3.imperial.ac.uk/pls/portallive/docs/1/1673903.JPG&w=573&h=722&ei=e1fXT9mlD8GQ2gXSxJy7Dw&zoom=1&iact=rc&dur=444&sig=101697176962587057094&page=1&tbnh=152&tbnw=121&start=0&ndsp=22&ved=1t:429,r:4,s:0,i:85&tx=23&ty=62 Christina Chu University of Alaska Fairbanks GEM 2012 Student Tutorial – Transient Phenomena at the Magnetopause and Bow Shock and Their Ground Signatures

Identifying HFAs Young/proto HFA Mature HFA Bx, By, Bz B n vx, vy, vz Zhang et al. [2010] Young/proto HFA Mature HFA Bx, By, Bz B n vx, vy, vz Ion E e- E Christina Chu University of Alaska Fairbanks GEM 2012 Student Tutorial – Transient Phenomena at the Magnetopause and Bow Shock and Their Ground Signatures

Extraterresterial HFAs Earth (intrinsic magnetic field) Venus (no intrinsic magnetic field) Mars (weak to no intrinsic magnetic field) Saturn (intrinsic magnetic field) Heliopause Images: http://library.thinkquest.org/12659/solar_system/venus/index.html, http://www.google.com/imgres?um=1&hl=en&client=firefox-a&sa=N&rls=org.mozilla:en-US:official&channel=fflb&authuser=0&biw=1318&bih=873&tbm=isch&tbnid=j24SHFoefBO6fM:&imgrefurl=http://sci.esa.int/science-e/www/object/index.cfm%3Ffobjectid%3D42898&docid=mc3KQpk4aMWjcM&imgurl=http://sci.esa.int/science-e-media/img/92/Heliosphere02-410.jpg&w=410&h=307&ei=YEzXT9amN6re2QWCzZCZDw&zoom=1&iact=rc&dur=519&sig=101697176962587057094&page=1&tbnh=157&tbnw=197&start=0&ndsp=20&ved=1t:429,r:2,s:0,i:81&tx=139&ty=102 Christina Chu University of Alaska Fairbanks GEM 2012 Student Tutorial – Transient Phenomena at the Magnetopause and Bow Shock and Their Ground Signatures

Venus HFA Slavin et al. [2009], Messenger Collinson et al. [2012], Venus Express Centered on IMF discontinuity Inward convective motional electric fields Decreased core magnetic field Christina Chu University of Alaska Fairbanks GEM 2012 Student Tutorial – Transient Phenomena at the Magnetopause and Bow Shock and Their Ground Signatures

Mars HFA Øieroset et al. [2001], Mars Global Surveyor Mars has no magnetopause – this eliminates HFA generation at planetary magnetopauses. Christina Chu University of Alaska Fairbanks GEM 2012 Student Tutorial – Transient Phenomena at the Magnetopause and Bow Shock and Their Ground Signatures

Saturn HFA Masters et al. [2009], Cassini 17 HFAs identified Christina Chu University of Alaska Fairbanks GEM 2012 Student Tutorial – Transient Phenomena at the Magnetopause and Bow Shock and Their Ground Signatures

HFA Simulated at Termination Shock Giacalone and Burgess [2010] 2D hybrid simulation of heliospheric current sheet and termination shock θCN = inclination of current sheet to shock normal HFA formation θCN < 60° Color indicates the final value of the total plasma density at the end of the simulation. Blue corresponds to densities equal to the starting density whereas red indicates plasma density that is four times the starting density. The direction of the magnetic field is indicated by the “+” (out of the page) and “-” (into the page) Original density = blue 4 x original density = red Christina Chu University of Alaska Fairbanks GEM 2012 Student Tutorial – Transient Phenomena at the Magnetopause and Bow Shock and Their Ground Signatures

Ionospheric Observations of HFAs Deformation of the magnetopause generates field-aligned currents (FACs) into the auroral ionosphere FAC signatures are measured on the ground as magnetic impulse events (MIEs) or traveling convection vortices (TCVs) [Glassmeier et al., 1989; Sitar et al., 1998] Sometimes, brightening of dayside aurora is observed coincident with HFA/TCV signatures Wong, C.Y.J. and Fillingim, M.O. [2011] Christina Chu University of Alaska Fairbanks GEM 2012 Student Tutorial – Transient Phenomena at the Magnetopause and Bow Shock and Their Ground Signatures

HFAs: Some Open Questions How are electrons being heated? How do HFA structures evolve with time? How do HFAs form? Are they related to the quasi-parallel or to the quasi- perpendicular shock? How do HFAs impact the magnetosphere and ionosphere? Christina Chu University of Alaska Fairbanks GEM 2012 Student Tutorial – Transient Phenomena at the Magnetopause and Bow Shock and Their Ground Signatures

Foreshock Region Property of collisionless plasma shocks Contains particles and waves associated with shock foreshock Bow shock magnetosphere Christina Chu University of Alaska Fairbanks GEM 2012 Student Tutorial – Transient Phenomena at the Magnetopause and Bow Shock and Their Ground Signatures

Foreshock Region E ExB Ecliptic plane Le and Russell [1994] E ExB Ecliptic plane http://www.google.com/imgres?q=ion+electron+foreshock&um=1&hl=en&rlz=1C1_____enUS432US432&biw=1280&bih=675&tbm=isch&tbnid=WnOxSpD4cugIKM:&imgrefurl=http://www-ssc.igpp.ucla.edu/~guan/papers/26AGU/&docid=Prv9tvKggDOwnM&imgurl=http://www-ssc.igpp.ucla.edu/~guan/papers/26AGU/fig01.gif&w=519&h=537&ei=B8fdT_rsC5Gk8QSUyuzYCg&zoom=1&iact=hc&vpx=273&vpy=113&dur=5213&hovh=228&hovw=221&tx=166&ty=140&sig=104635802392315429521&page=1&tbnh=148&tbnw=143&start=0&ndsp=17&ved=1t:429,r:11,s:0,i:107 Christina Chu University of Alaska Fairbanks GEM 2012 Student Tutorial – Transient Phenomena at the Magnetopause and Bow Shock and Their Ground Signatures

Foreshock Cavities Foreshock Caviton Bulk flow nearly identical to the solar wind. Decrease in magnetic field and density Temperature and pressure inside are slightly greater than that in the solar wind. Foreshock Caviton Like foreshock cavity but is immersed in sea of ULF waves Blanco-Cano et al. [2011] Christina Chu University of Alaska Fairbanks GEM 2012 Student Tutorial – Transient Phenomena at the Magnetopause and Bow Shock and Their Ground Signatures

Foreshock Compressional Boundaries Simulations showing the foreshock compressional boundary at different Alfven mach numbers. Formation: expansion of foreshock with strong wave particle interactions. Associated with density and magnetic field decrease below solar wind levels. Omidi et al. [2009] Christina Chu University of Alaska Fairbanks GEM 2012 Student Tutorial – Transient Phenomena at the Magnetopause and Bow Shock and Their Ground Signatures

Foreshock Bubbles Omidi et al. [2010] Turner et al. [2011] http://naca.larc.nasa.gov/search.jsp?R=20110022646&qs=Ns%3DPublication-Date|1%26N%3D4294756232 Christina Chu University of Alaska Fairbanks GEM 2012 Student Tutorial – Transient Phenomena at the Magnetopause and Bow Shock and Their Ground Signatures

Density Holes Regions of space where the density suddenly falls by ten times but the temperature of the remaining gas leaps from 1e5 ºC to 1e7 ºC. Are different from hot flow anomalies Density holes are shorter in duration than HFAs http://www.esa.int/esaSC/SEMX66L8IOE_index_2.html Christina Chu University of Alaska Fairbanks GEM 2012 Student Tutorial – Transient Phenomena at the Magnetopause and Bow Shock and Their Ground Signatures

Magnetopause Reconnection Large-scale properties of reconnection at the magnetopause The physics of magnetic reconnection at the dayside magnetopause Quasi-steady versus time dependent reconnection at the dayside magnetopause Plasma transport including particle entry and energization through reconnection and diffusive processes at the dayside magnetospheric boundary Impacts of the bow shock/magnetosheath and the cusp/ionosphere systems on dayside magnetopause reconnection Christina Chu University of Alaska Fairbanks GEM 2012 Student Tutorial – Transient Phenomena at the Magnetopause and Bow Shock and Their Ground Signatures

Magnetopause Reconnection NIMF SIMF Christina Chu University of Alaska Fairbanks GEM 2012 Student Tutorial – Transient Phenomena at the Magnetopause and Bow Shock and Their Ground Signatures

Flux Transfer Events ISEE 1 and 2 saw signatures that looked like multiple magnetopause crossings It was determined that those signatures were magnetic ropes on the magnetosphere boundary Plasma within magnetosheath FTE's flows at or above the surrounding magnetosheath flow velocity Mixture of magnetospheric and magnetosheath plasma. http://www-ssc.igpp.ucla.edu/personnel/russell/papers/magpause/mp24.gif ALSO good FTE explaination Christina Chu University of Alaska Fairbanks GEM 2012 Student Tutorial – Transient Phenomena at the Magnetopause and Bow Shock and Their Ground Signatures

Flux Transfer Events Slide from zhang themis fte pdf, http://www.spaceplasma.unh.edu/wiki/images/2/25/Zhang_UNH_themis-cluster_FTE.pdf Christina Chu University of Alaska Fairbanks GEM 2012 Student Tutorial – Transient Phenomena at the Magnetopause and Bow Shock and Their Ground Signatures

Questions? Again, why should we care? Solar wind disruptions (ie in density, magnetic field, etc.) can be carried through bow shock causing changes in magnetosheath which can lead to surface waves in the magnetopause Questions? Christina Chu University of Alaska Fairbanks GEM 2012 Student Tutorial – Transient Phenomena at the Magnetopause and Bow Shock and Their Ground Signatures

Extra Slides Christina Chu University of Alaska Fairbanks GEM 2012 Student Tutorial – Transient Phenomena at the Magnetopause and Bow Shock and Their Ground Signatures

Identifying HFAs Christina Chu Zhang et al. [2010] Christina Chu University of Alaska Fairbanks GEM 2012 Student Tutorial – Transient Phenomena at the Magnetopause and Bow Shock and Their Ground Signatures

Flux Ropes in HFAs Flux Ropes Helical field structures with core fields Often have current sheets at edges (to separate it from the surrounding plasma) Guide field is often present – creates twisted flux rope, with twist field wrapped around an axis of guide field Mulligan, Russell, Luhmann [2000] Interplanetary Magnetic Clouds: Statistical patterns and radial variations; mulligan, russell, luhmann Russell and Elphic Christina Chu University of Alaska Fairbanks GEM 2012 Student Tutorial – Transient Phenomena at the Magnetopause and Bow Shock and Their Ground Signatures

Plasma Entry to Mantle Mantle de-energized magnetosheath plasma densities: few times 0.01 - 1 cm-3 temperatures: ~100 eV tailward flow velocities: 100-200 km/s Velocity Filter Effect Low-energy ions (blue) take longer to mirror from the ionosphere than higher energy ions (red), Low-energy ions are convected further across field lines, As one moves towards the magnetosphere, have decreasing energy and density (with deeper penetration into the mantle). https://wiki.oulu.fi/display/SpaceWiki/Magnetospheric+boundary+layer Christina Chu University of Alaska Fairbanks GEM 2012 Student Tutorial – Transient Phenomena at the Magnetopause and Bow Shock and Their Ground Signatures