In the presence of a strong magnetic field, accretion discs surrounding neutron stars, black holes, and white dwarfs have their inner edges at their Alfvén radii, i.e., at the distance where magnetic energy density becomes equal to the kinetic energy density. Young stars, X-ray binaries, active galactic nuclei possess discs which could generate jets. Jets arise at the inner boundary of the disc at the Alfvén radius when magnetic field is sufficiently strong. We emphasize here that not only accretion discs possess this feature. The inner edge of the heliospheric current sheet is located at the solar Alfvén radius. The inner edges of the Jovian magnetodisc and Saturnian ring current are also placed close to their Alfvén radii. Thus, in the presence of a strong magnetic field the inner edges of a lot of astrophysical discs are located at Alfvén radii regardless of the nature of their origin, material, and motion direction. This means that discs under such conditions are well described by MHD theory.
M. L. Khodachenko, I. Alexeev, E. Belenkaya, H. Lammer, J.-M. Griessmeier, M. Leitzinger, P. Odert, T. Zaqarashvili and H. O. Rucker, “Magnetospheres of ‘Hot Jupiters’: The Importance of Magnetodisks for Shaping of Magnetospheric Obstacle,” The Astrophysical Journal, Vol. 744, No. 1, 2012, pp. 70-86. doi:10.1088/0004-637X/744/1/70
I. I. Alexeev, “The Penetration of Interplanetary Magnetic and Electric Fields into the Magnetosphere,” Journal of Geomagnetism and Geoelectricity, Vol. 38, No. 11, 1986, pp. 1199-1221. doi:10.5636/jgg.38.1199
I. I. Alexeev and E. S. Belenkaya, “Modeling of the Jovian Magnetosphere,” Annales Geophysicae, Vol. 23, No. 3, 2005, pp. 809-826. doi:10.5194/angeo-23-809-2005
I. I. Alexeev, E. S. Belenkaya, S. Yu. Bobrovnikov, J. A. Slavin and M. Sarantos, “Paraboloid Model of Mercury’s Magnetosphere,” Journal of Geophysical Research, Vol. 113, No. A12210, 2008. doi:10.1029/2008JA013368
V. Beskin, “Magnetohydrodynamic Models of Astrophysical Jets,” Physics-Uspekhi, Vol. 53, No. 12, 2010, pp. 1241-1278. doi:10.3367/UFNe.0180.201012b.1241
Y. N. Istomin, “Synchrotron Radiation of a Pulsar Wind,” Astrophys and Space Science, Vol. 331, No. 1, 2011, pp. 127-133. doi:10.1007/s10509-010-0421-z
A. M. Cherepashchuk, “Highly Evolved Close Binary Stars,” Space Science Reviews, Vol. 74, No. 3-4, 1995, pp. 313-324. doi:10.1007/BF00751417
A. M. Cherepashchuk, “X-Ray Nova Binary Systems,” Space Science Reviews, Vol. 93, No. 3-4, 2000, pp. 473- 580. doi:10.1023/A:1026507625481
A. M. Cherepashchuk, “Observational Manifestations of Precession of Accretion Disk in the SS 433 Binary System,” Space Science Reviews, Vol. 102, No. 1-4, 2002, pp. 23-25. doi:10.1023/A:1021356630889
P. Ghosh and F. K. Lamb, “Accretion by Rotating Magnetic Neutron Stars. III—Accretion Torques and Period Changes in Pulsating X-Ray Sources” The Astrophysical Journal, Vol. 234, 1979, pp. 296-316. doi:10.1086/157498
K. S. Cheng, K. N. Yu and K. Y. Ding, “X-Ray and Gamma-Ray Emission from Active Galactic Nuclei,” Astronomy & Astrophysics, Vol. 275, 1993, pp. 53-60.
P. Ghosh and F. K. Lamb, “Accretion by Rotating Magnetic Neutron Stars. II—Radial and Vertical Structure of the Transition Zone in Disk,” The Astrophysical Journal, Vol. 232, 1979, pp. 259-276. doi:10.1086/157285
U. Torkelsson, “Magnetic Torques between Accretion Discs and Stars,” Monthly Notices of the Royal Astronomical Society, Vol. 298, No. 3, 1998, pp. L55-L59. doi:10.1046/j.1365-8711.1998.01927.x
X.-D. Li, “Evolution of the Inner Radius of the Accretion Disk in the X-Ray Pulsar A0535+26,” The Astrophysical Journal, Vol. 476, No. 1, 1997, pp. 278-280. doi:10.1086/303624
V. F. Shvartsman, “Two Generations of Pulsars,” Radiofizika, Izvestiya vyzshich uchebnych zavedeniy, Vol. 13, No. 12, 1970, pp. 1852-1867.
V. F. Shvartsman, “The Influence of Stellar Wind on Accretion,” Astronomicheskii Zhurnal, Vol. 47, No 3, 1970, pp. 660-662.
A. F. Illarionov and R. A. Sunyaev, “Why the Number of Galactic X-Ray Stars is so Small?” Astronomy & Astrophysics, Vol. 39, 1975, pp. 185-195.
N. I. Shakura and R. A. Sunyaev, “Black Holes in Binary Systems. Observational Appearance,” Astronomy & Astrophysics, Vol. 24, 1973, pp. 337-355.
D. Zhang and Z. G. Dai, “Hyperaccreting Discs around Magnetars for Gamma-Ray Bursts: Effects of Strong Magnetic Fields,” The Astrophysical Journal, Vol. 718, No. 2, 2010, p. 841. doi:10.1088/0004-637X/718/2/841
B. D. Metzger, T. A. Thompson and E. Quataert, “On the Conditions for Neutron-Rich Gamma-Ray Burst Outflows,” The Astrophysical Journal, Vol. 676, No. 2, 2008, pp. 1130-1150. doi:10.1086/526418
W. Bednarek, “TeV Gamma-Rays from Accreting Magnetars in Massive Binaries,” Monthly Notices of the Royal Astronomical Society, Vol. 397, No. 3, 2009, pp. 1420-1425. doi:10.1111/j.1365-2966.2009.14893.x
V. L. Ginzburg, “On Physics and Astrophysics,” Bureau Quantum, Moscow, 1995.
M. Kuperus, “Magnetohydrodynamics of Accretion Disks,” Computer Physics Reports, Vol. 12, No. 4, 1990, pp. 275- 278. doi:10.1016/0167-7977(90)90014-W
J. Frank, A. R. King and D. Raine, “Accretion Power in Astrophysics,” 2nd Edition, Cambridge University Press, Cambridge, 1992.
Y.-M. Wang, “Location of the Inner Radius of a Magnetically Threaded Accreation Disk,” The Astrophysical Journal, Vol. 465, No. 2, 1996, pp. L111-L113. doi:10.1086/310150
W. Bednarek and J. Pabich, “X-Rays and γ-Rays from Cataclysmic Variables: The Example Case of Intermediate Polar V1223 Sgr,” Monthly Notices of the Royal Astronomical Society, Vol. 411, No. 3, 2011, pp. 1701-1706. doi:10.1111/j.1365-2966.2010.17800.x
A. G. Zhilkin and D. V. Bisikalo, “Magnetic-Field Structure in the Accretion Disks of Semi-Detached Binary Systems,” Astronomy Reports, Vol. 54, No. 9, 2010, pp. 840- 852. doi:10.1134/S1063772910090088
A. M. Cherepashchuk, “Search for Black Holes,” Physics-Uspekhi, Vol. 46, No. 4, 2003, pp. 335-371. doi:10.1070/PU2003v046n04ABEH001282
N. G. Bochkarev and C. M. Gaskell, “The Accuracy of Supermassive Black Hole Masses Determined by the Single-Epoch Spectrum (Dibai) Method,” Astronomy Letters, Vol. 35, No. 5, 2009, pp. 287-293. doi:10.1134/S1063773709050016
J. A. Tomsick, K. Yamaoka, S. Corbel, P. Kaaret, E. Kalemci and S. Migliari, “Truncation of the Inner Accretion Disk around a Black Hole at Low Luminosity,” The Astrophysical Journal, Vol. 707, No. 1, 2009, pp. L87- L91. doi:10.1088/0004-637X/707/1/L87
J. M. Miller, C. S. Reynolds, A. C. Fabian, E. M. Cackett, G. Miniutti, J. Raymond, D. Steeghs, R. Reis and J. Homan, “Initial Measurements of Black Hole Spin in GX 339-4 from Suzaku Spectroscopy,” The Astrophysical Journal, Vol. 679, No. 2, 2008, pp. L113-L116. doi:10.1086/589446
R. Penrose and R. M. Floyd, “Extraction of Rotational Energy from a Black Hole,” Nature Physical Science, Vol. 229, No. 6, 1971, pp. 177-179.
S. Koide and K. Arai, “Energy Extraction from Rotating Black Hole by Magnetic Reconnection in the Ergosphere,” The Astrophysical Journal, Vol. 682, 2008, pp. 1124-1133. doi:10.1086/589497
S. Chandrasekhar and L. Woltjer, “On Force-Free Magnetic Fields,” Proceedings of the National Academy of Sciences of the United States of America, Vol. 44, No. 4, 1958, pp. 285-289. doi:10.1073/pnas.44.4.285
E. E. Salpeter, “Accretion of Interstellar Matter by Massive Objects,” The Astrophysical Journal, Vol. 140, 1964, pp. 796-800. doi:10.1086/147973
Ya. B. Zeldovich, “A Fate of a Star and Release of Gravitation Energy during Accretion,” Transactions (Doklady) of the USSR Academy of Sciences, Vol. 155, No. 1, 1964, pp. 67-70.
Ya. B. Zeldovich and I. D. Novikov, “The Theory of the Gravitation and Stars Evolution,” Nauka, Moskow, 1971.
C. Fendt and J. Greiner, “Magnetically Driven Superluminal Motion from Rotating Black Holes: Solution of the Magnetic Wind Equation in Kerr Metric,” Astronomy & Astrophysics, Vol. 369, No. 1, 2001, pp. 308-322. doi:10.1051/0004-6361:20010108
H. Alfvén and P. Carlqvist, “Interstellar Clouds and the Formation of Stars,” Astrophysics and Space Science, Vol. 55, No. 2, 1978, pp. 487-509. doi:10.1007/BF00642272
T. Kudoh, “Electromagnetic Fields inside Thin Accretion Discs around Rotating Black Holes,” Monthly Notices of the Royal Astronomical Society, Vol. 266, No. 5, 1994, pp. 609-613.
A. Tomimatsu and M. Takahashi, “Black Hole Magnetospheres around Thin Disks Driving inward and outward Winds,” The Astrophysical Journal, Vol. 552, No. 2, 2001, pp. 710-717. doi:10.1086/320575
D. A. Levine, D. F. Figer, M. Morris and I. S. McLean, “A Circumstellar H2O Maser Associated with the Circumnuclear Molecular Disk at the Galactic Center?” The Astrophysical Journal, Vol. 447, No. 2, 1995, pp. L101- L104. doi:10.1086/309583
W. J. Duschl, “On the Inner Edge of the Circumnuclear Disc in the Galaxy,” Monthly Notices of the Royal Astronomical Society, Vol. 240, No. 1, 1989, pp. 219-223.
B. Volmer and W. J. Duschl, “The Stability of the Circumnuclear Disk Clouds in the Galactic Centre,” Astronomy & Astrophysics, Vol. 377, No. 3, 2001, pp. 1016-1022.
L. J. Greenhill, A. Tilak and G. Madejski, “Prevalence of High X-Ray Obscuring Columns among AGNs that Host H2O Masers,” The Astrophysical Journal, Vol. 686, No. 1, 2008, pp. L13-L16. doi:10.1086/592782
M. Szymczak, T. Pillai and K. M. Menten, “Masers as Signposts of High-Mass Protostars. A Water Maser Survey of Methanol Maser Sources,” Astronomy and Astrophysics, Vol. 434, No. 2, 2005, pp. 613-621. doi:10.1051/0004-6361:20042437
B. K. Wallin and W. D. Watson, “Water in X-Irradiated Environments at the Nucleir of Active Galaxies,” The Astrophysical Journal, Vol. 476, No. 2, 1997, pp. 1734-1742. doi:10.1086/303641
C. S. Reynolds, M. A. Nowak, S. Markoff, J. Tueller, J. Wilms and A. J. Young, “Probing the Accretion Disk and Central Engine Structure of NGC 4258 with Suzaku and XMM-Newton Observations,” The Astrophysical Journal, Vol. 691, No. 2, 2009, pp. 1159-1167. doi:10.1088/0004-637X/691/2/1159
M. Camenzind, “Compact Objects in Astrophysics: White Dwarfs, Neutron Stars and Black Holes,” In: G. Bцrner, A. Burkert, W. B. Burton, et al., Eds., Astronomy and Astrophysics Library, Springer-Verlag Berlin Heidelberg, Leipzig, 2007, pp. 355-572. doi:10.1007/978-3-540-49912-1
M. Elitzur and I. Shlosman, “The AGN-Obscuring Torus: The End of the ‘Doughnut’ Paradigm?” The Astrophysical Journal Letters, Vol. 648, No. 2, 2006, pp. L101-L104. doi:10.1086/508158
M. Livio, “Astrophysical Jets: A Phenomenological Examination,” Physics Reports, Vol. 311, No. 3-5, 1999, pp. 225-245. doi:10.1016/S0370-1573(98)00102-1
T. K. Suzuki, “Self-Consistent Simulations of Alfven Waves Driven Winds from the Sun and Stars,” Space Science Reviews, Vol. 158, No. 2-4, 2011, pp. 339-363. doi:10.1007/s11214-010-9709-0
R. E. Pudritz, R. Ouyed, C. Fendt and A. Brandenburg, “Disk Winds, Jets and Outflows: Theoretical and Computational Foundations,” In: B. Reipurth, D. Jewitt and K. Keil, Eds., Protostars and Planets V, University of Arizona Press, Tucson, 2006, pp. 277-294.
A. A. Vidotto, M. Opher, V. Jatenco-Pereira and T. I. Gombosy, “Simulations of Winds of Weak-Lined T Tauri stars: The Magnetic Field Geometry and the Influence of the Wind on Giant Planet Migration,” The Astrophysical Journal, Vol. 703, No. 2, 2009, pp. 685-691. doi:10.1088/0004-637X/703/2/1734
P. A. Bespalov and V. V. Zhelyaznyakov, “Formation of Disks around Hot Magnetic Stars under the Action of Radiation Pressure,” Pisma v Astronomischeskii Zhurnal, Vol. 16, 1990, pp. 1030-1044.
W. Bednarek, “High Energy Neutrinos from Binary Systems of Two Massive Stars,” Proceedings 29th International Cosmic Ray Conference, Pune, 3-10 August 2005, pp. 101-104.
N. U. Crooker, C.-L. Huang, S. M. Lamassa, D. E. Larson, S. W. Kahler and H. E. Spence, "Heliospheric Plasma Sheets," Journal of Geophysical Research, Vol. 109, No. A03107, 2004. doi:10.1029/2003JA010170
X. P. Zhao and J. T. Hoeksema, “The Magnetic Field at the Inner Boundary of the Heliosphere around Solar Minimum,” Solar Physics, Vol. 266, No. 2, 2010, pp. 379-390. doi:10.1007/s11207-010-9618-0
E. S. Belenkaya, “The Jovian Magnetospheric Magnetic and Electric Fields: Effects of the Interplanetary Magnetic Field,” Planetary and Space Science, Vol. 52, No. 5-6, 2004, pp. 499-511. doi:10.1016/j.pss.2003.06.008
T. W. Hill, A. J. Dessler and F. C. Michel, “Configuration of the Jovian Magnetosphere,” Geophysical Research Letters, Vol. 1, No. 1, 1974, pp. 3-6. doi:10.1029/GL001i001p00003
T. W. Hill, “Inertial Limit on Corotation,” Journal of Geophysical Research, Vol. 84, No. A11, 1979, pp. 6554- 6558. doi:10.1029/JA084iA11p06554
D. D. Barbosa, “A Two-Dimensional Radial Outflow Model of Plasma at Jupiter,” Planetary and Space Science, Vol. 35, No. 1, 1978, pp. 119-125. doi:10.1016/0032-0633(87)90150-4
F. V. Coroniti and C. F. Kennel, “Possible Origins of Time Variability in Jupiter’s Outer Magnetosphere,” Geophysical Research Letters, Vol. 4, No. 6, 1977, pp. 211-214. doi:10.1029/GL004i006p00211
P. A. Delamere and F. Bagenal, “Solar Wind Interaction with Jupiter’s Magnetosphere,” Journal of Geophysical Research, Vol. 115, No. A10201, 2010. doi:10.1029/2010JA015347
L. A. Frank, B. G. Burek, K. L. Ackerson, J. H. Wolfe and J. D. Mihalov, “Plasma in Saturn’s Magnetosphere,” Journal of Geophysical Research, Vol. 85, No. A11, 1980, pp. 5695-5708. doi:10.1029/JA085iA11p05695
E. J. Bunce and S. W. H. Cowley, “A Note on the Ring Current in Saturn’s Magnetosphere: Comparison of Magnetic Data Obtained during the Pioneer-11 and Voyager-1 and -2 Fly-Bys,” Annales Geophysicae, Vol. 21, No. 3, 2003, pp. 661-669. doi:10.5194/angeo-21-661-2003
J. E. P. Connerney, M. H. Acuna and N. F. Ness, “Currents in Saturn’s magnetosphere,” Journal of Geophysical Research, Vol. 88, No. A11, 1983, pp. 8779-8789. doi:10.1029/JA088iA11p08779
S. Kellett, C. S. Arridge, E. J. Bunce, A. J. Coates, S. W. H. Cowley, M. K. Dougherty, A. M. Persoon, N. Sergis and R. J. Wilson, “Nature of the Ring Current in Saturn’s Dayside Magnetosphere,” Journal of Geophysical Research, Vol. 115, No. A08201, 2010. doi:10.1029/2009JA015146
E. S. Belenkaya, I. I. Alexeev, V. V. Kalegaev and M. S. Blokhina, “Definition of Saturn’s Magnetospheric Model Parameters for the Pioneer 11 Flyby,” Annales Geophysicae, Vol. 24, No. 3, 2006, pp. 1145-1156. doi:10.5194/angeo-24-1145-2006
O. Cohen, J. J. Drake, V. L. Kashyap, I. V. Sokolov and T. I. Gombosy, “The Impact of Hot Jupiters on the Spin-Down of Their Host Stars,” The Astrophysical Journal Letters, Vol. 723, No. 1, 2010, pp. L64-L67. doi:10.1088/2041-8205/723/1/L64
I. I. Alexeev, V. V. Kalegaev, E. S. Belenkaya, S. Y. Bobrovnikov, E. J. Bunce, S. W. H. Cowley and J. D. Nichols, “A Global Magnetic Model of Saturn’s Magnetosphere, and a Comparison with Cassini SOI Data,” Geophysical Research Letters, Vol. 33, No. L08101, 2006. doi:10.1029/2006GL025896
E. S. Belenkaya, S. W. H. Cowley, S. V. Badman, M. S. Blokhina and V. V. Kalegaev, “Dependence of the Open-Closed Field Line Boundary in Saturn’s Ionosphere on both the IMF and Solar Wind Dynamic Pressure: Comparison with the UV Auroral oval Observed by the HST,” Annales Geophysicae, Vol. 26, No. 1, 2008, pp. 159-166. doi:10.5194/angeo-26-159-2008
E. S. Belenkaya, I. I. Alexeev, M. S. Blokhina, E. J. Bunce, S. W. H. Cowley, J. D. Nichols, V. V. Kalegaev, V. G. Petrov and G. Provan, “IMF Dependence of Saturn’s Auroras: Modelling Study of HST and Cassini Data from 12-15 February 2008,” Annales Geophysicae, Vol. 28, No. 8, 2010, pp. 1559-1570. doi:10.5194/angeo-28-1559-2010
V. Beskin and A. Tchekhovskoy, “Internal Structure of Thin Accretion Disks,” In: A. M. Fridman, M. Ya. Marov, I. G. Kovalenko, Eds., Astrophysical Disks, Springer, Dordrecht, 2006, pp. 55-74.
V. Beskin, “Axisymmetric Stationary Flows in Compact Astrophysical Objects,” Physics-Uspekhi, Vol. 167, No 7, 1997, pp. 689-720. doi:10.3367/UFNr.0167.199707a.0689
T. Lery and A. Frank, “Structure and Stability of Keplerian Magnetohydrodynamic Jets,” The Astrophysical Journal, Vol. 533, No. 2, 2000, pp. 897-910. doi:10.1086/308683
M. K. Abubekerov and V. M. Lipunov, “The Lower Temperature Limit of Accretors,” Astronomy Reports, Vol. 47, No. 8, 2003, pp. 681-686. doi:10.1134/1.1601636
J. Ferreira and P. O. Petrucci, “Jet Launching and Field Advection in Quasi-Keplerian Discs,” In: G. E. Romero, R. A. Sunyaev and T. Belloni, Eds., Proceedings of the IAU Symposium, “Jets at All Scales,” International Astronomical Union, Vol. 275, No. S275, 2010, pp. 260- 263.
R. Narayan and E. Quataert, “Black Hole Accretion,” Science, Vol. 307, No. 5706, 2005, pp. 77-80. doi:10.1126/science.1105746