複数のX-lineを形成する磁気リコネクションでの電子加速 / Elecron Acceleration during Magnetic Reconnection with multiple X-lines

by Tsubasa Yumura

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ෳ਺ͷ X-line Λܗ੒͢Δ ࣓ؾϦίωΫγϣϯͰͷిࢠՃ଎ ౦ژେֶେֶӃɹཧֶܥݚڀՊ ஍ٿ࿭੕Պֶઐ߈ɹӉ஦࿭੕Պֶେߨ࠲ ౻ຊݚڀࣨɹ౬ଜɹཌྷ

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໨࣍ 1. ং࿦ 2. γϛϡϨʔγϣϯ 3. ෳ਺ͷ X-line ͷޮՌ 4. ύϥϝʔλઃఆґଘੑ 5. ݁࿦ 2

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໨࣍ 1. ং࿦ 2. γϛϡϨʔγϣϯ 3. ෳ਺ͷ X-line ͷޮՌ 4. ύϥϝʔλઃఆґଘੑ 5. ݁࿦ 3

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࣓ؾϦίωΫγϣϯ 4 ࣓ؾϦίωΫγϣϯɿ࣓ྗઢ͕ܨ͗׵ΘΔʢre- connectionʣ ESA ϛΫϩεέʔϧͰൃੜ 㱺 େن໛ߏ଄ʹൃల ൓ฏߦͳ࣓৔ͱڥք૚ిྲྀ B ࣓৔ B ࣓৔ J ిྲྀ

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Ӊ஦ϓϥζϚதͷ࣓ؾϦίωΫγϣϯ 5 ଠཅίϩφϧʔϓ (NASA TRACE) ͔ʹ੕Ӣ (NASA Chandra, Hubble) ஍ٿ࣓ؾݍͱ GEOTAIL Ӵ੕ (JAXA) •  ଠཅ •  ࣓ؾݍڥքɾ࣓ؾݍඌ෦ •  ߴΤωϧΪʔఱମ •  Ӊ஦ϓϥζϚͷΤωϧΪʔ ։์ݱ৅ͱͯ͠ॏཁ

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࣓ؾϦίωΫγϣϯిࢠՃ଎ 6 •  ਓ޻Ӵ੕(GEOTAIL, Cluster ౳)ʹΑΔ஍ٿ࣓ؾݍͷͦͷ৔؍ ଌ •  γϛϡϨʔγϣϯʹΑΔՃ଎ϝΧχζϜղ໌ –  X-line ෇ۙͷ meandering/Speiser ӡಈ [Speiser, 1965] –  pileup ྖҬͰͷ ∇BυϦϑτ/࿷ۂυϦϑτ [Hoshino et al., 2001 JGR] •  ୯Ұͳ X-line Λ༩͑ΔγϛϡϨʔγϣϯϞσϧ͕ओྲྀ X-line pileup ྖҬ

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ෳ਺ͷ X-line Λܗ੒͢ΔϦίωΫγϣϯ 7 Chen et al. (2007) ຊݚڀͷ໨త ෳ਺ͷ X-line Λܗ੒͢Δ࣓ؾϦίωΫ γϣϯͰͷిࢠՃ଎ϝΧχζϜΛղ໌͢Δ •  ஍ٿ࣓ؾݍඌ෦΍ଠཅ෩தͰ؍ଌ͞ΕΔ •  X-line ؒͷด࣓ͨ͡ྗઢɿ࣓ؾౡ –  ؍ଌɿ࣓ؾౡͱߴΤωϧΪʔిࢠ [Chen et al., 2007] –  ࣓ؾౡ͸߹ମ͢Δ [Finn and Kaw, 1977] –  γϛϡϨʔγϣϯɿ࣓ؾౡ߹ମͱిࢠՃ଎ [Saito and Sakai, 2006] ࣓ؾౡ X-line

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໨࣍ 1. ং࿦ 2. γϛϡϨʔγϣϯ 3. ෳ਺ͷ X-line ͷޮՌ 4. ύϥϝʔλઃఆґଘੑ 5. ݁࿦ 8

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εʔύʔίϯϐϡʔλ 9 Ӊ஦Պֶݚڀຊ෦ Space Science Simulator (SSS) JAXA

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ཻࢠγϛϡϨʔγϣϯ •  Maxwell ํఔࣜ •  ཻࢠͷӡಈํఔࣜ 10 ∇×B = cµ0 J+ E /c ∇×E = ʵ B /c m v = q(E + v×B/cγ) m = γm0 γ = (1-v2/c2)-1/2 ཻࢠҠಈ F → v → x ిՙɾిྲྀີ౓ x → ρ, v → J Maxwell ํఔࣜ ρ, J → E , B ӡಈํఔࣜ E , B → F ɾ ɾ ɾ PIC (particle in-cell) ๏

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γϛϡϨʔγϣϯઃఆ 11 ॳظ৚݅ɿHarris ܕిྲྀ૚ n(z) = n0 /cosh2(z/d) + n1 Bx (z) = B0 tanh(z/d) Bx n z z 2 ࣍ݩγϛϡϨʔγϣϯ x z y Lx Lz Bx

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1. ং࿦ 2. γϛϡϨʔγϣϯ 3. ෳ਺ͷ X-line ͷޮՌ 4. ύϥϝʔλઃఆґଘੑ 5. ݁࿦ ໨࣍ 12

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݁Ռɿ୯Ұͳ X-line Λ༩͑Δ৔߹ 13 ne /n0 0 1 48 24 0 0 12 -12 x /λi z /λi ిࢠີ౓

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݁Ռɿෳ਺ͷ X-line Λ༩͑Δ৔߹ 14 ne /n0 0 1 48 24 0 0 12 -12 x /λi z /λi ిࢠີ౓

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࣓ؾౡ߹ମͷൃల 15 •  Lx=48 nm=8 Ͱ͸࣓ؾౡ਺ 8→2 , 2→1 ͷ̎ஈ֊߹ମ ࣓ؾதੑ໘ (z=0) Ͱͷిࢠີ౓

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࣓ؾౡ߹ମͱిࢠՃ଎ 16 ࣓ؾதੑ໘ (z=0) Ͱͷిࢠີ౓ ΤωϧΪʔεϖΫτϧ ΤωϧΪʔɿε=γ-1 •  1ஈ֊໨߹ମ (8→2) ʹେ෯ʹΤωϧΪʔ૿Ճ •  ߹ମͷ߹͍ؒ(t=30ʙ34) ͸΄ͱΜͲΤωϧΪʔ૿Ճͳ͠ •  ిࢠՃ଎͸࣓ؾౡ߹ମʹରԠ͢Δ

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ߴΤωϧΪʔిࢠͷۭؒ෼෍ <#> 17 0ɹɹ ɹɹ ɹ80 counts / cell Ωi T = 40 Ωi T = 20 Ωi T = 30 Ωi T = 10 ߴΤωϧΪʔ (ε > 1) ిࢠ਺ •  ୯Ұͳ X-line ͷ৔߹ɺ࣓ؾౡΛ ғΉϦϯάঢ়෼෍Λܗ੒ •  ઌߦݚڀͰ΋ಉ༷ͷߏ଄

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ߴΤωϧΪʔిࢠͷۭؒ෼෍ 18 Ωi T = 20 Ωi T =30 Ωi T = 34 Ωi T = 38 0ɹ ɹ80 Counts / cell Ωi T = 40 Ωi T = 50 •  2 ஈ֊߹ମʹΑΓ̎ॏϦϯάঢ়෼෍Λܗ੒ ߴΤωϧΪʔ (ε > 1) ిࢠ਺

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ిࢠՃ଎ྖҬͷಛఆ 19 •  ి৔͕ిࢠʹ୯Ґ࣌ؒ͋ͨΓʹ༩͑ΔΤωϧΪʔɹJeɾE •  JeɾE ͕େ͖͍ྖҬʢԼਤͷ੺͍ྖҬʣ͸ిࢠՃ଎ྖҬ •  X-line, pileup ྖҬʹՃ࣓͑ؾౡ߹ମྖҬ΋Ճ଎ྖҬ

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࣓ؾౡ߹ମྖҬͰͷՃ଎ 20 Ωi T = 30 Ωi T = 34 Ωi T = 38 •  ࣓ؾౡ߹ମྖҬͰΤωϧΪʔεϖΫτϧΛऔಘ •  ࣓ؾౡ߹ମ࣌ʹΤωϧΪʔ૿Ճ

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࣓ؾౡ߹ମྖҬͰͷՃ଎ 21 Ey Vey 0.0 2 -0.09 0 5 0 -3 •  X-line ͱಉ༷ͷߏ଄ •  Ey ͰՃ଎ •  ࣓ؾౡ߹ମ࣌ʹܗ੒͢Δ X-line ͰՃ଎ -12 12 0 z x z y Vex Vey

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Ճ଎ཻࢠ(ε>25)ͷيಓ 22 X-line ࣓ؾౡ߹ମ pileup energy - time energy - x z- x •  30ݸͷ௒ߴΤωϧΪʔ(ε>25)ిࢠͷཻࢠيಓΛௐ΂ͨ •  શͯͷిࢠ͸ X-line ͰՃ଎Λड͚ͨ •  ଟ͘ͷిࢠ͸ X-line ͷޙʹpileup ྖҬ and/or ࣓ؾౡ߹ ମྖҬͰՃ଎Λड͚͍ͯͨ ΤωϧΪʔɿε=γ-1

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໨࣍ 23 1. ং࿦ 2. γϛϡϨʔγϣϯ 3. Multiple X-line ͷޮՌ 4. ύϥϝʔλઃఆґଘੑ – ܭࢉྖҬͷେ͖͞ґଘੑ 5. ݁࿦

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ܭࢉྖҬͷେ͖͞ґଘੑ 24 ܭࢉ ܭࢉྖҬͷେ͖͞ Lx × Lz (λi) ॳظͷ࣓ؾౡα Πζ(λi) ॳظͷ࣓ؾౡ਺ ̍ 48 × 32 6 8 ̎ 24 × 32 6 4 ̏ 96 × 64 6 16 •  n ∝ ε-α ͰϑΟοςΟϯά

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ܭࢉྖҬͷେ͖͞ґଘੑ •  ϦίωΫγϣϯεέʔϧͱΤωϧΪʔ૿Ճ – શମɿ͓͓Αͦઢܗ – ࣓ؾౡ߹ମྖҬɿඇઢܗ •  εέʔϧ֦େ → ߹ମྖҬͷՃ଎େɹɹɹɹ → ඇ೤తిࢠͷੜ੒૿Ճ 25 શମ ࣓ؾౡ߹ମྖҬ ̑ഒ 2ഒ 2ഒ

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1. ং࿦ 2. γϛϡϨʔγϣϯ 3. Multiple X-line ͷޮՌ 4. ύϥϝʔλઃఆґଘੑ 5. ݁࿦ ໨࣍ 26

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݁࿦ •  ࣓ؾౡͷଟஈ֊߹ମʹΑΓߴΤωϧΪʔి ࢠ͸ଟॏϦϯά෼෍Λܗ੒͢Δɿ؍ଌ΁ͷد ༩ •  X-line ͱ pileup ྖҬʹՃ࣓͑ؾౡ߹ମྖҬ ΋ిࢠΛՃ଎͢Δɿ৽ͨͳཻࢠՃ଎ϝΧχζ Ϝ •  ௒ߴΤωϧΪʔిࢠͷੜ੒͸ෳ਺ͷՃ଎ྖ ҬʹΑΔଟஈ֊Ճ଎͕ॏཁ •  ϦίωΫγϣϯͷεέʔϧ֦େͱͱ΋ʹ࣓ 27

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݁࿦ •  X-line ͰՃ଎Ͱ͖ ΔΤωϧΪʔʹ͸ ݶք͕͋Δ •  ͞ΒͳΔՃ଎͸ pile ྖҬ and/or ࣓ؾ ౡ߹ମྖҬͰಘΒ ΕΔ 28

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֤ిࢠՃ଎ྖҬͰͷΤωϧΪʔ૿Ճ 29 ୯Ґ࣌ؒ౰ͨΓͷΤωϧΪʔ૿Ճ ΤωϧΪʔ૿Ճͷ૯ྔ •  Ճ଎ྖҬຖʹΤωϧΪʔ૿ՃΛൺֱ •  pileup ྖҬ͕શମͷΤωϧΪʔ૿Ճʹ࠷΋د༩͢Δ •  ࣓ؾౡ߹ମՃ଎͸ଞͷྖҬͱൺ΂ͯখ͍͞ ∫JeɾE dSɹSɿ֤Ճ଎ྖҬͷ໘ੵ ∬JeɾE dSdtɹ

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ܭࢉྖҬͷେ͖͞ґଘੑ •  ిྲྀ૚໘ੵͰن֨Խ •  ϦίωΫγϣϯͷεέʔϧ͕େ͖͘ͳ ΔʹͭΕΤωϧΪʔ͕૿Ճ͢Δ 30

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ܭࢉྖҬͷେ͖͞ґଘੑ •  X-line , pileup ྖҬɿ̎ഒ •  ࣓ؾౡ߹ମྖҬɿ̐ഒ •  ࣓ؾϦίωΫγϣϯͷεέʔϧ͕֦େ ͢Δͱ࣓ؾౡ߹ମྖҬͷد༩͕૿Ճ͢ Δɹ→ɹඇ೤తిࢠͷੜ੒ͷ૿Ճ 31 ܭࢉ̏ɹ96 × 64 ܭࢉ̍ɹ48 × 32

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pileup ྖҬͰͷՃ଎ 32 •  pileup ྖҬ (|Bz| େ) Ͱڧ͍ Ey •  ∇B υϦϑτ •  ࿷ۂυϦϑτ ∇B v ∝ ʵB×∇B // ʵ y v ∝ ʵR×B // ʵ y x z y B R

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࣓ؾౡ߹ମ vs. SXL 33 run Mass Ratio Space(λi ) nm GF D(λi ) perturbation 1 100 48 × 32 8 0 0.5 GEM 2 100 48 × 32 8 0 0.5 GEM 3 100 48 × 32 SXL 0 0.5 Gaussian

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ΨΠυ࣓৔ґଘੑ 34 run Mass Ratio Space(λi ) nm GF D(λi ) perturbation 1 100 48 × 32 8 0 0.5 GEM 5 100 48 × 32 8 0.5 0.5 GEM

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݁࿦ (2/2) •  ௒ߴΤωϧΪʔిࢠ͸ X-line ͰͷՃ଎ޙʹ pileup ྖҬ and/or ࣓ؾౡ߹ମྖҬͰ͞Β ʹՃ଎Λड͚ͯੜ੒͞ΕΔ •  ϦίωΫγϣϯͷεέʔϧͱͱ΋ʹ࣓ؾౡ ߹ମྖҬͰͷՃ଎͸ݦஶʹͳΓଟ਺ͷඇ೤ తిࢠΛੜ੒͢Δ 35