DOI: 10.3724/SP.J.1085.2013.00296

Advances in Polar Science 2013/24:4 PP.296-314

Global distributions of storm-time ionospheric currents as seen in geomagnetic field variations

To investigate temporal and spatial evolution of global geomagnetic field variations from high-latitude to the equator during geomagnetic storms,we analyzed ground geomagnetic field disturbances from high latitudes to the magnetic equator.The daytime ionospheric equivalent current during the storm main phase showed that twin-vortex ionospheric currents driven by the Region 1 field-aligned currents(R1 FACs)are intensified significantly and expand to the low-latitude region of~30°magnetic latitude.Centers of the currents were located around 70°and 65°in the morning and afternoon,respectively.Corresponding to intensification of the R1 FACs,an enhancement of the eastward/westward equatorial electrojet occurred at the daytime/nighttime dip equator.This signature suggests that the enhanced convection electric field penetrates to both the daytime and nighttime equator.During the recovery phase,the daytime equivalent current showed that two new pairs of twin vortices,which are different from two-cell ionospheric currents driven by the R1 FACs,appear in the polar cap and mid latitude.The former led to enhanced northward Bz(NBZ)FACs driven by lobe reconnection tailward of the cusps,owing to the northward interplanetary magnetic field(IMF).The latter was generated by enhanced Region 2 field-aligned currents(R2 FACs).Associated with these magnetic field variations in the mid-latitudes and polar cap,the equatorial magnetic field variation showed a strongly negative signature,produced by the westward equatorial electrojet current caused by the dusk-to-dawn electric field.

Key words:solar wind,interplanetary magnetic field,geomagnetic storm,convection electric field,field-aligned currents,equatorial electrojet,NBZ FAC system

ReleaseDate:2015-04-16 13:27:18

1 Nishida A, Iwasaki N, Nagata T. The origin of fluctuations in the equatorial electrojet: A new type of geomagnetic variation. Ann Geophys, 1966, 22: 478-484.

2 Nishida A. Coherence of geomagnetic DP2 magnetic fluctuations with interplanetary magnetic variations. J Geophys Res, 1968, 73(17): 5549-5559, doi: 10.1029/JA073i017p05549.

3 Kikuchi T, Luhr H, Kitamura T, et al. Direct penetration of the polar electric field to the equator during a DP2 event as detected by the auroral and equatorial magnetometer chains and the EISCAT radar. J Geophys Res, 1996, 101(A8): 17161-17173, doi: 10.1029/96JA01299.

4 Kikuchi T, Araki T, Maeda H, et al. Transmission of polar electric fields to the equator. Nature, 1978, 273(5664): 650-651, doi: 10.1038/273650a0.

5 Kikuchi T,Araki T. Horizontal transmission of the polar electric field to the equator. J Atmos Terr Phys, 1979, 41(9): 927-936, doi: 10.1016/0021-9169(79)90094-1.

6 Hirono M. A theory of diurnal magnetic variations in equatorial regions and conductivity of the ionosphere E region. J Geomag Geoelectr, 1952, 4(1): 7-21, doi: 10.5636/jgg.4.7.

7 Baker W G, Martyn D F. Electric currents in the ionosphere. I. The conductivity, Phil Trans R Soc London A, 1953, 246(913): 281-294, doi: 10.1098/rsta.1953.0016.

8 Araki T. A physical model of the geomagnetic sudden commencement// Solar Wind Sources of Magnetospheric Ultra-Low-Frequency Waves. Washington, D. C.: AGU, 1994: 183-200.

9 Shinbori A, Tsuji Y, Kikuchi T, et al. Magnetic latitude and local time dependence of the amplitude of geomagnetic sudden commencements. J Geophys Res, 2009, 114(A4): A04217, doi: 10.1029/2008JA013871.

10 Shinbori A, Tsuji Y, Kikuchi T, et al. Magnetic local time and latitude dependence of amplitude of the main impulse (MI) of geomagnetic sudden commencements and its seasonal variation. J Geophys Res, 2012, 117(A8): A08322, doi: 10.1029/2012JA018006.

11 Motoba T, Kikuchi T, Luhr H, et al. Global Pc5 caused by a DP 2-type ionospheric current system. J Geophys Res, 2002, 107(A2): SMP 8-1-SMP 8-12, doi: 10.1029/2001JA900156.

12 Nishida A, Kamide Y. Magnetospheric processes preceding the onset of an isolated substorm: A case study of the March 31, 1978, substorm. J Geo-phys Res, 1983, 88(A9): 7005-7014, doi: 10.1029/JA088iA09p07005.

13 Kikuchi T, Pinnock M, Rodger A, et al. Global evolution of a substorm-associated DP2 current system observed by SuperDARN and magnetometers. Adv Space Res, 2000, 26(1): 121-124, doi: 10.1016/S0273-1177(99)01037-6.

14 Kikuchi T, Luhr H, Schlegel K, et al. Penetration of auroral electric fields to the equator during a substorm. J Geophys Res, 2000, 105(A10): 23251-23261, doi: 10.1029/2000JA900016.

15 Wilson G R, Burke W J, Maynard N C, et al. Global electrodynamics observed during the initial and main phases of the July 1991 magnetic storm. J Geophys Res, 2001, 106(A11): 24517-24539, doi: 10.1029/2000JA 000348.

16 Kikuchi T, Hashimoto K K, Nozaki K. Penetration of magnetospheric electric fields to the equator during a geomagnetic storm. J Geophys Res, 2008, 113(A6): A06214, doi: 10.1029/2007JA012628.

17 Tsuji Y, Shinbori A, kikuchi,et al. Magnetic latitude and local time distributions of ionospheric currents during a geomagnetic storm. J Geophys Res, 2012, 117(A7): A07318, doi: 10.1029/2012JA017566.

18 Vasyliunas V M. Mathematical models of magnetospheric convection and its coupling to the ionosphere // Particles and Fields in the Magnetosphere. Hingham, MA: D. Reidel. Pub. Co., 1970: 60-71.

19 Vasyliunas V M. The interrelationship of magnetospheric processes // Earth's Magnetospheric Processes. Norwell, MA: D. Reidel. Pub. Co., 1972: 29-38.

20 Jaggi R K, Wolf R A. Self-consistent calculation of the motion of a sheet of ions in the magnetosphere. J Geophys Res, 1973, 78(16): 2852-2866, doi: 10.1029/JA078i016p02852.

21 Southwood D J. The role of hot plasma in magnetospheric convection. J Geophys Res, 1977, 82(35): 5512-5520, doi: 10.1029/JA082i035p05512.

22 Senior C, Blanc M. On the control of magnetospheric convection by the spatial distribution of ionospheric conductivities. J Geophys Res, 1984, 89(A1): 261-284, doi: 10.1029/JA089iA01p00261.

23 Somayajulu V V, Reddy C A, Viswanathan K S. Penetration of magneto-spheric convective electric field to the equatorial ionosphere during the substorm of March 22, 1979. Geophys Res Lett, 1987, 14(8): 876-879, doi: 10.1029/GL014i008p00876.

24 Peymirat C, Richmond A D, Kobea A T. Electrodynamic coupling of high and low latitudes: Simulations of shielding/overshielding effects. J Geophys Res, 2000, 105(A10): 22991-23003, doi: 10.1029/2000JA000057.

25 Rastogi R G, Patel V L. Effect of interplanetary magnetic field on ionosphere over the magnetic equator. Proc Indiana Acad Sci, 1975, 82(4): 121-141.

26 Kelley M C, Fejer B G, Gonzales C A. An explanation for anomalous equatorial ionospheric electric fields associated with a northward turning of the interplanetary magnetic field. Geophys Res Lett, 1979, 6(4): 301-304, doi: 10.1029/GL006i004p00301.

27 Fejer B G, Gonzales C A, Farley D T, et al. Equatorial electric fields during magnetically disturbed conditions 1. The effect of the interplanetary magnetic field. J Geophys Res, 1979, 84(A10): 5797-5802, doi: 10.1029/ JA084iA10p05797.

28 Gonzales C A, Kelley M C, Fejer B G, et al. Equatorial electric fields during magnetically disturbed conditions 2. Implications of simultaneous auroral and equatorial measurements. J Geophys Res, 1979, 84(A10): 5803-5812, doi: 10.1029/JA084iA10p05803.

29 Rastogi R G. Geomagnetic storms and electric fields in the equatorial ionosphere. Nature, 1977, 268(5619): 422-424, doi: 10.1038/268422a0.

30 Rastogi R G Midday reversal of equatorial ionospheric electric field. Ann Geophys, 1997, 15(10): 1309-1315, doi:10.1007/s00585-997-1309-2.

31 Kikuchi T, Hashimoto K K, Kitamura T I, et al. Equatorial counterelectrojets during substorms. J Geophys Res, 2003, 108(A11): 1406, doi: 10.1029/2003JA009915.

32 De Zeeuw D L, Sazykin S, Wolf R A, et al. Coupling of a global MHD code and an inner magnetospheric model: Initial results. J Geophys Res, 2004, 109(A12): A12219, doi: 10.1029/2003JA010366.

33 Shinbori A, Nishimura Y, Ono T, et al. Electrodynamics in the duskside inner magnetosphere and plasmasphere during a super magnetic storm on March 13-15, 1989. Earth Planets Space, 2005, 57(7): 643-659.

34 Nishimura Y, Shinbori A, Ono T, et al. Storm-time electric field distribution in the inner magnetosphere. Geophys Res Lett, 2006 33(22): L22102, doi: 10.1029/2006GL027510.

35 Yeh H-C, Foster J C, Rich F J, et al. Storm time electric field penetration observed at mid-latitude. J Geophys Res, 1991, 96(A4): 5707-5721, doi: 10.1029/90JA02751.

36 Foster J C, Rich F J. Prompt midlatitude electric field effects during severe geomagnetic storms. J Geophys Res, 1998, 103(A11): 26367-26372, doi: 10.1029/97JA03057.

37 Baker J B H, Greenwald R A, Ruohoniemi J M, et al. Observations of ionospheric convection from the Wallops SuperDARN radar at middle latitudes. J Geophys Res, 2007, 112(A1): A01303, doi: 10.1029/2006JA 011982.

38 Kikuchi T, Ebihara Y, Hashimoto K K, et al. Penetration of the convection and overshielding electric fields to the equatorial ionosphere during a quasiperiodic DP 2 geomagnetic fluctuation event. J Geophys Res, 2010,115(A5): A05209, doi: 10.1029/2008JA013948.

39 Tanaka Y, Shinbori A, Hori T, et al. Analysis software for the upper atmosphere data developed by the IUGONET project and its application to the polar science. Adv Polar Sci, 2013, 24(4): 231-240.

40 Hayashi H, Koyama Y, Hori T, et al. Inter-university upper atmosphere global observation network (IUGONET). Data Sci J, 2013, 12: WDS179.

41 Le G, Russell C T, Takahashi K. Morphology of the ring current derived from magnetic field observations. Ann Geophys, 2004, 22(4): 1267-1295, doi: 10.5194/angeo-22-1267-2004.

42 Araki T, Funato K, Iguchi T, et al. Direct detection of solar wind dynamic pressure effect on ground geomagnetic field. Geophys Res Lett, 1993, 20(9): 775-778, doi: 10.1029/93GL00852.

43 Huang C-S, Foster J C, Kelley M C. Long-duration penetration of the interplanetary electric field to the low-latitude ionosphere during the main phase of magnetic storms. J Geophys Res, 2005, 110(A11): A11309, doi: 10.1029/2005JA011202.

44 Fejer B G, Jensen J W, Kikuchi T, et al. Equatorial ionospheric electric fields during the November 2004 magnetic storm. J Geophys Res, 2007, 112(A10): A10304, doi: 10.1029/2007JA012376.

45 Heelis R A, Mohapatra S. Storm time signatures of the ionospheric zonal ion drift at middle latitudes. J Geophys Res, 2009, 114(A2): A02305, doi: 10.1029/2008JA013620.

46 Huang C S. Continuous penetration of the interplanetary electric field to the equatorial ionosphere over eight hours during intense geomagnetic storms. J Geophys Res, 2008, 113(A11): A11305, doi: 10.1029/2008JA 013588.

47 Burke W J, Maynard N C, Hagan M P, et al. Electrodynamics of the inner magnetosphere observed in the dusk sector by CRRES and DMSP during the magnetic storm of June 4-6, 1991. J Geophys Res, 1998, 103(A12): 29399-29418, doi: 10.1029/98JA02197.

48 Wygant J, Rowland D, Singer H J, et al. Experimental evidence on the role of the large spatial scale electric field in creating the ring current. J Geophys Res, 1998, 103(A12): 29527-29544, doi: 10.1029/98JA01436.

49 Ebihara Y, Ejiri M. Simulation study on fundamental properties of the storm-time ring current. J Geophys Res, 2000, 105(A7): 15843-15859, doi: 10.1029/1999JA900493.

50 Ebihara Y, Ejiri M. Numerical simulation of the ring current: Review. Space Sci Rev, 2003, 105(1-2): 377-452, doi: 10.1023/A:1023905607888.

51 Terada N, Iyemori T, Nose M, et al. Storm-time magnetic field variations observed by the ETS-VI satellite. Earth Planet Space, 1998, 50: 853-864.

52 Ebihara Y, Ejiri M, Nilsson H, et al. Statistical distribution of the storm-time proton ring current: POLAR measurements. Geophys Res Lett, 29(20): 30-1-30-4, doi: 10.1029/2002GL015430.

53 Hashimoto K K, Kikuchi T, Ebihara Y. Response of the magnetospheric convection to sudden interplanetary magnetic field changes as deduced from the evolution of partial ring currents. J Geophys Res, 2002, 107(A11): SMP 1-1-SMP 1-14, doi: 10.1029/2001JA009228.

54 Liemohn M W, Kozyra J U, Thomsen M F, et al. Dominant role of the asymmetric ring current in producing the stormtime Dst. J Geophys Res, 2001, 106(A6): 10883-10904, doi: 10.1029/2000JA000326.

55 Yu Y Q, Ridley A J, Welling D T, et al. Including gap region field-aligned currents and magnetospheric currents in the MHD calculation of ground-based magnetic field perturbations. J Geophys Res, 2010, 115(A8): A08207, doi: 10.1029/2009JA014869.

56 Wolf R A, Harel M, Spiro R W, et al. Computer simulation of inner mag-netospheric dynamics for the magnetic storm of July 29, 1977. J Geophys Res, 1982, 87(A8): 5949-5962, doi: 10.1029/JA087iA08p05949.

57 Abdu M A, Maruyama T, Batista I S, et al. Ionospheric responses to the October 2003 superstorm: Longitude/local time effects over equatorial low and middle latitudes. J Geophys Res, 2007, 112(A10): A10306, doi: 10.1029/2006JA012228.

58 Tsunomura S. Numerical analysis of global ionospheric current system including the effect of equatorial enhancement. Ann Geophys, 1999, 17(5): 692-706, doi: 10.1007/s00585-999-0692-2.

59 Kamide Y, Yasuhara F, Akasofu S I. On the cause of northward magnetic field along the negative X axis during magnetospheric substorms. Planet Space Sci, 1974, 22(8): 1219-1229, doi: 10.1016/0032-0633(74)90006-3.

60 Reddy C A, Kumar S A, Somayajulu V V. An observational test for the ionospheric or magnetospheric origin of night-time geomagnetic positive bays at low and mid-latitudes. Planet Space Sci, 1988, 36(11): 1149-1154, doi: 10.1016/0032-0633(88)90069-4.

61 Kikuchi T, Tsunomura S, Hashimoto K, et al. Field-aligned current effects on midlatitude geomagnetic sudden commencements. J Geophys Res, 2001, 106(A8): 15555-15565, doi: 10.1029/2001JA900030.

62 Sastri J H. Penetration electric fields at the nightside dip equator associated with the main impulse of the storm sudden commencement of 8 July 1991. J Geophys Res, 2002, 107(A12): SIA 9-1-SIA 9-8, doi: 10.1029/ 2002JA009453.

63 Araki T, Keika K, Kamei T, et al. Nighttime enhancement of the amplitude of geomagnetic sudden commencements and its dependence on IMF-5z. Earth Planets Space, 2006, 58(1): 45-50.

64 Dungey J W. The structure of the exosphere, or adventures in velocity space//DeWitt C, Hieblot J, LeBeau L. Geophysics: The earth's environment. New York: Gordon and Breach, 1963: 503-550.

65 Song P, Russell C T. Model of the formation of the low-latitude boundary layer for strongly northward interplanetary magnetic field. J Geophys Res,1992, 97(A2): 1411-1420.

66 Phan T, Frey H U, Frey S, et al. Simultaneous Cluster and IMAGE observations of cusp reconnection and auroral proton spot for northward IMF. Geophys Res Lett, 2003, 30(10): 1509, doi: 10.1029/2003GL016885.

67 Trattner K J, Fuselier S A, Petrinec S M. Location of the reconnection line for northward interplanetary magnetic field. J Geophys Res, 2004, 109(A3): A03219, doi: 10.1029/2003JA009975.

68 Iijima T, Potemra T A, Zanetti L J, et al. Large-scale Birkeland currents in the dayside polar region during strongly northward IMF: A new Birkeland current system. J Geophys Res, 1984, 89(A9): 7441-7452.

69 Zanetti L J, Potemra T A, Iijima T, et al. Ionospheric and Birkeland current distributions for northward interplanetary magnetic field: Inferred polar convection. J Geophys Res, 1984, 89(A9): 7453-7458.

70 Iijima T, Shibaji T. Global characteristics of northward IMF-associated (NBZ) field-aligned currents. J Geophys Res, 1987, 92(A3): 2408-2424.

71 Cowley S W H. Magnetosphere-ionosphere interactions: A tutorial review //Magnetospheric current systems. Washington D.C.: AGU, 2000: 91-106.

72 Iijima T, Fujii R, Hesse M, et al. Field-aligned currents in geospace: Substance and significance//Magnetospheric current systems. Washington D.C.: AGU, 2000: 107-129.

73 Maezawa K. Magnetospheric convection induced by the positive and negative Z components of the interplanetary magnetic field: Quantitative analysis using polar cap magnetic records. J Geophys Res, 1976, 81(3): 2289-2303.

74 Burch J L, Reiff P H, Menietti J D, et al. IMF 5y-dependent plasma flow and Birkeland currents in the dayside magnetosphere: 1. Dynamics Explorer observations. J Geophys Res, 1985, 90(A2): 1577-1593.

75 Erickson, Goncharenko L P, Nicolls M J, et al. Dynamics of north American sector ionospheric and thermospheric response during the November 2004 superstorm. J Atmos Solar-Terr Phys, 2010, 72(4): 292-301, doi: 10.1016/j.jastp.2009.04.001.