プラズマ雑誌会 速報
2004年4月21日
Pevtsov, A. A. et al. (2003) ApJ 598, 1387
The Relationship Between X-ray Radiance and Magnetic Flux
(太陽、恒星、前主系列星の磁束とX線光度の関係に関する経験則を導出)
Schwadron, N. A. and McComas, D. J. (2003) ApJ 599, 1395
Solar Wind Scaling Law
(高速風と低速風の統一モデル、簡単なスケーリング則を導出)
Meier, D. L. and Nakamura, M. (2003)
in Proc. 3D Signatures in Stellar Exlplosions,
a workshop honoring J. C. Wheeler's 6oth Birthday, 10-13 June 2003,
MHD Supernova Jets: The Missing Link (astro-ph 0312050)
(宇宙ジェット、ガンマ線バースト、惑星状星雲の統一モデル、図がおもしろ
い)
Pevtsov, A. A. et al. (2003) ApJ 598, 1387
The Relationship Between X-ray Radiance and
Magnetic Flux
現代(磁気的)加熱説
• アルフベン波説
Uchida-Kaburaki 1974. Wenzel 1974,
Hollweg 1981, Sakurai-Granik 1984
Kudoh-Shibata 1999 ほか多数
• ナノフレア説
Parker 1988
ほか多数
アルフベン波説(Kudoh,Shibata
1999)
Nanoflare 説
加熱率の磁場強度依存性?
• アルフベン波説
F = fρV^2 V_A ∝ B
• ナノフレア説
F=f B^2 V/4π ∝ B^2
• フレア(maximum reconnection heating
rate)
F=f B^2 V_A/ 4π∝ B^3
最新ようこう観測
• Shimizu(1996)PhD thesis
活動領域コロナは
microflare/nanoflare だらけ!
=>
ナノフレア加熱???
• Yashiro(2000)PhD thesis
Lx(活動領域) ∝ B^1.07
F ∝ B
=> アルフベン波加熱???
活動領域における
Total X-ray flux vs. total magnetic flux
(Yashiro 2000)
恒星コロナ
ほとんどの恒星にコロナが存在
1)表面対流層のない星にもコロナ
2)X線光度 ∝ 回転速度^2
3)X線フラックス∝ 表面(平均)磁場
Stellar corona in HR diagram
Stellar X-ray luminosity vs.
rotation velocity
Stellar X-ray flux vs. magnetic
field strength
Pevtsov, A. A. et al. (2003) ApJ 598, 1387
The Relationship Between X-ray Radiance and Magnetic Flux
(太陽、恒星、前主系列星の磁束とX線光度の関係に関する経験則を導出)
Schwadron, N. A. and McComas, D. J. (2003) ApJ 599,
1395
Solar Wind Scaling Law
Schwadron, N. A. and McComas, D. J. (2003) ApJ 599, 1395
Solar Wind Scaling Law
(高速風と低速風の統一モデル、簡単なスケーリング則を導出)
Fig
Meier, D. L. and Nakamura, M. (2003)
in Proc. 3D Signatures in Stellar Exlplosions,
a workshop honoring J. C. Wheeler's 6oth
Birthday, 10-13 June 2003,
MHD Supernova Jets: The Missing Link
(astro-ph 0312050)
Quasar(QSO: 3C273)
Looks like a star, but
actually a nucleus of
galaxies
=> Active Galactic Nulei
(AGN)
Distance ~ 100M pc
=> huge energy release
rate ~1046 erg/s
Total released energy
~1062 erg
optical
Most energetic ojbect in
our universe
Radio Galaxy(Cygnus A): AGN
(distance=150Mpc、length=100kpc)
Radio/VLA
Protostellar Jet (HH1/2)
(length ~ 1 pc)
Optical/ Hubble
Accretion disk (tori) was
revealed at footpoint of AGN
jets
Accretion disk at the footpoint of
protostellar jets
Jets from close binary system
SS433 jet
(radio、velocity=0.26c)
SS433 jet
(X-ray/ASCA)
Superluminal motion in jets from
close binary system (microquasar)
(jet velocity ~ 1.25 c、
GRS1915+1015)
AGN jets
often show
superlumina
l motion
Apparent speed
is 10 c !
Summary of Characteristics of
Astrophysical Jets
AGN
Jet length
Close binary protostar
system
Supermassi Black hole
protostar
ve
or neutron
black hole
star
1 Mpc
3 pc
0.3 pc
Jet velocity
c
0.3c - c
100km/s
Escape
velocity
c
0.3c - c
100km/s
Central
object
Planetary nebula
Crab nubula
X-ray (CHANDRA)
magnetic field and rotation are
essential condition for jet formation
chandra_pulsar_jet_B150958_p011016.1.jpg
3. MHD model of astrophysical jets
Accelerate jets by magnetic field and rotation
Magnetic field line
jet
Accretion disk
Protostar, black hole
Centrifugal
force
Magnetic
pressure
Blandford-Payne 1982, Lovelace et al 1986,
Pudritz-Norman 1986, Uchida-Shibata 1985, Shu et al. 1994, …
Magneto-centrifugal force
beads
wire
rotation
Centrifugal
force
Magnetic pinch due to helically twisted
magnetic field (toroidal field) collimate jets
First computer simulation of
MHD jets from accretion disk
磁力線
円盤
Time
Jet velocity ~ Kepler veloicty
(rotation velocity of the disk)
Shibata & Uchida (1990、
1986)
MHD jet with bow shock
(Kudoh et al. 2000)
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