Laboratory of Auroras

Primary objective

Investigation of coupling processes in the solar wind-magnetosphere-ionosphere system, as well as the structure of the magnetosphere and dynamics of various magnetispheric domains.

Principal scientific investigation

Study of physical phenomena occurring in the solar wind-magnetosphere-ionosphere system under disturbed geomagnetic conditions and in response to sharp changes in the interplanetary medium on the basis of ground-based auroral observations in the daytime and nighttime auroral oval and direct measurements of particle precipitation on spacecraft.

Current research tasks

• structure and dynamics of different auroral precipitation regions under magnetic storm and substorm conditions;
• hemispheric power of different types of auroral precipitation at all phases of the magnetospheric substorm;
• features of auroral precipitation in the dayside polar cusp and their relation to the interplanetary medium conditions;
• traveling convection vortexes: their occurrence, characteristics and relationship with the IMF and solar wind plasma;
• spatio-temporal characteristics of nighttime auroras during stormtime substorms as compared to the classical scheme of the auroral substorm;
• fine structure and dynamics of polar auroras in the periods of “double” auroral oval;
• characteristics of pulsing auroras and geomagnetic pulsations in different MLT sectors and their connection with interplanetary medium parameters and geomagnetic activity level;
• features of the Schumann resonance as observed at auroral and polar cap latitudes;

Some of the recent scientific results

• Energy contribution of different type electron precipitation has been estimated in 3-hour midday and midnight sectors at all substorm phases. It is shown that on the dayside the greatest energy with ~ 2 GW maximum is observed in the diffuse auroral zone at the final stage of substorm recovery. On the nightside, the greatest precipitation power with maximum of ~ 20 GW is revealed in the auroral oval near substorm expansion maximum.
• For the first time, a model of hemispheric electron precipitation power during magnetospheric substorm has been developed based on direct DMSP F6 and F7 observations. The model enables to calculate analytically the average precipitation power at all phases of substorm of any intensity and duration. The computations indicate that at the final stage of substorm expansion, the global precipitation power increases from about 30 GW for substorm with AL=-150 nT to 140 GW for substorm with AL=-1000 nT. For an average substorm (AL=-400 nT) with the duration of ~ 2.5 hours the global energy of electron precipitation is ~ 300 TJ.
• Analyses of TV observations at Spitsbergen archipelago with applying digital methods of TV image processing revealed weak subvisual auroral arcs (SVA) located 3- 4° poleward of more intense auroral oval arcs. While SVA-arcs were mainly observed during northward IMF Bz conditions, their extension was latitudinal and not sun-aligned. The spectrum of precipitating electrons had maximum within the range of 0.4-1.0 keV, which corresponds to 150-200 km altitude of the aurora. It is the SVA-arcs that presumably determine the polar cap boundary, which earlier was thought to be associated with the poleward edge of the oval.
• Rare events of isolated polar cap arc generation and cases of multiple active sun-aligned arc occurrence have been investigated. Spatio-temporal characteristics of isolated arcs were derived. It is shown that the process of active polar cap arc generation reveals manifestations of a special type polar cap auroral breakup.
• Auroral intensity variations and dynamics of discrete and diffuse auroras prior to substorm expansion and in breakup progressing have been examined. It was found that the breakup onset is stimulated by visual and subvisual auroral structures moving to the breakup site from local regions of active auroras located east or west of the breakup arcs. The main regularities in the behavior of a pre-breakup arc and surrounding auroras in the time interval T0±20 min were studied.
• DMSP observations of precipitating electrons show that at maximum of substorm expansion and at the initial stage of substorm recovery, the auroral precipitation boundaries in the midnight sector are located at higher (lower) latitudes under low (high) values of the solar wind dynamic pressure. The conditions of low (high) solar wind dynamic pressure are considered as referred to Pd<3 nPa (Pd>3 nPa).
• Auroral precipitation boundaries during giant magnetic storms have been investigated by DMSP observations. It was shown that in such periods, the poleward boundary of electron precipitation in the nighttime sector locates at about 72° CGL and depends weakly on the magnetic activity level. Well pronounced correlation between the equatorward shift of the poleward boundary of daytime precipitation and the position of the equatorward boundary of nighttime precipitation was found. This result testifies to the close connection between the erosion of the dayside magnetosphere and the energy of auroral precipitation and shows that checking of the dayside precipitation boundaries can serve a good tool for monitoring the precipitation power during magnetic disturbances.
• Structure and dynamics of nighttime auroras observed during substorms occurring at different stages of magnetic storm have been investigated. It was found that the most pronounced discrepancy from the classical substorm scheme is observed during the main phase of magnetic storm, which is characterized by equatorward moving weak auroral activations similar to pseudo-breakups or small substorms. The substorms occurring at the end of the storm main phase are displayed as fast explosive expansions of unstructured auroral luminosity in all directions.
• It is shown that in some SC events, the time scle of the increase in the geomagnetic field observed at the low latitude stations and on spacecraft in the dayside magnetosphere is less than that of the increase in the solar wind dynamic pressure. It is assumed that this feature may be associated with the influence of a secondary rarefaction wave, arising in the magnetosheath during interaction of an interplanetary shock wave with the bow shock–magnetopause system.
• Two-stage morningside auroral response to magnetosphere coupling with a solar wind dynamic pressure pulse (SC) has been found during a magnetic calm period under northward IMF Bz conditions. It is shown that just after SC, a gradual smooth auroral activation occurs, which is followed by a 4-5 min delayed bursty intensification of diffuse aurorae and appearance of multiple bright discrete auroras in a wide latitudinal region. Auroral luminosity variations with periods of 4-6 min (Pc5 regime) were registered in diffuse aurorae which correlated well with geomagnetic H component pulsations.
• A comparison of photometer and magnetic data at Barentsburg observatory shows that the Pc4-5 regular geomagnetic pulsations are accompanied by similar pulsations in auroral luminosity. This suggests that geomagnetic pulsations observed on the Earth’s surface can be a magnetic effect of the 3D current system, whose extra ionospheric part is spatially coincident with precipitating electron fluxes.
• It is shown that positive-to-negative change of sign in IMF Bz-component may cause generation of geomagnetic Pc5 pulsations. It is assumed that Pc5 pulsations observed in such periods are associated with FTE events on the dayside magnetopause.
• Spatio-temporal properties of Pc5 pulsations in the cosmic noise absorption (CNA) don’t repeat those of geomagnetic Pc5 pulsations. It is supposed that CNA Pc5 pulsations can originate from interaction of two weakly connected oscillating systems: the magnetospheric Alfvén resonator and the electrons interacting with electron-cyclotron waves.
• Variations of three magnetic components of VLF emission in the 0.1-10 Hz frequency range have been examined by using the data of Barentsburg and Lovozero observatories. Parameters of the polarization ellipse of the first Schumann resonance (7.8 Hz) at both observatories were determined in horizontal and vertical planes. It was discovered that the polarization vector rotates mainly clockwise at both stations.
• Variations of interplanetary parameters on the Earth’s orbit in compound streams from different solar sources have been investigated. It is shown that there is no mixing of interplanetary plasma, so that in a time sequence of interacting streams any of them happens to dominate.
• Ground-based and satellite observations of auroras have been used to examine auroral luminosity features in the periods of Earth’s magnetosphere interaction with solar wind streams from isolated solar sources. It is shown that the highest values of intensity ratio I630.0/I557.7 (0.5-1.5) are observed in the auroras when the Earth is in the flare streams or disappearing filament streams. For these types of streams the lowest latitudinal positions of the auroral equatorward boundary were observed (54°-56° CGL). The lowest values of I630.0/I557.7 ratio (~ 0.1-0.3) are typical for the periods of the Earth being in the body of the high speed streams from coronal holes. The highest latitudinal positions of the auroral equatorward boundary (64°-66° CGL) were associated with the heliospheric current sheet.

Experimental facilities

Optical and magnetometer observations from Barentsburg, Lovozero and Loparskaya observatories of Polar Geophysical Institute.

Equipment:

• all-sky TV cameras
• spectrographs
• a set of photometers
• three component Bobrov type magnetometers
• induction magnetometers

Grants and Projects

Russian Foundation for basic research grants:
94-05-16273a and 96-05-64222a: Geophysical phenomena in the dayside high-latitude ionosphere and their relationship to the magnetospheric structure and processes at the magnetopause.
96-05-64273а: Research of magnetospheric processes during auroral substorm development from the ground-based observations of polar aurorae.
99-05-65117а: Spatial distribution and dynamics of high latitude aurorae and their relation to magnetospheric structure and processes at the magnetopause.
02-05-64807а: The structure of high-latitude precipitation and magnetosphere-ionosphere coupling processes.
06-05-64374а: Features of a global distribution of auroral precipitation in their connection with magnetospheric structure and interplanetary medium parameters.
09-05-00818а: Analysis of magnetospheric condition according to ground-based observations of aurorae and spacecraft observations of auroral precipitation features.

Program of the Presidium of the RAS: «Changes in the environment and climate: natural catastrophes». Project 4.2: «Structure of auroral precipitation and mechanisms of polar aurora generation».

Program of the Presidium of the RAS: «Environment in changeable climate conditions: extreme natural phenomena and catastrophes». Project: «Structure and dynamics of high-latitude aurorae and auroral precipitation and their relationship with the magnetospheric structure and magnetosphere-ionosphere coupling processes».

Scientific relations

• Sodankyla Geophysical Observatory, Sodankyla, Finland
• Finnish Meteorological Institute, Helsinki, Finland
• Solar-Terrestrial Influences Laboratory, Bulgarian Academy of Sciences, Stara Zagora
• Department of Physics, University of Oslo, Oslo, 0105 Norway
• Applied Physics Laboratory (APL), The Johns Hopkins University, Laurel, Maryland, USA
• Swedish Institute of Space Physics, Sweden
• University of Texas at Dallas, Richardson, USA
• Saint Peterburg State University, Saint Petersburg, Russia
• Pushkov Institute of Terrestrial Magnetism, Ionosphere, and Radiowave Propogation, Russian Academy of Sciences (IZMIRAN), Troitsk, Moscow region
• Central Astronomical Observatory at Pulkovo of RAS, Saint Petersburg
• Schmidt Institute of the Physics of the Earth, Russian Academy of Sciences, Moscow, Russia
• Skobeltsyn Institute of Nuclear Physics Moscow State University, Moscow, Russia
• Space Research Institute RAS, Moscow, Russia

Principal publications

Vorobjev V.G., Rezhenov B.V., Yagodkina O.I. The solar wind plasma density control of night-time auroral particle precipitation // Ann. Geophys. V.22. №. 3. P. 1047-1052. 2004.

Roldugin V.C., Maltsev Y.P., Vasiljev A.N., Schokotov A.Y. and Belyajev G.G. Schumann resonance frequency increase during solar X-ray bursts // J. Geophys. Res. V. 109. No. A1. doi:10.1029/2003JA010019. 2004.

Roldugin V.C., Maltsev Y.P., Vasiljev A.N., Schokotov A.Y. and Belyajev G.G. Diurnal variations of Schumann resonance frequency in NS and EW magnetic components // J. Geophys. Res. V. 109. No. A8, A08304 10.1029/2004JA010487. 2004.

Roldugin V.C, Tinsley B.A. Atmospheric transparency changes associated with solar wind-induced atmospheric electricity variations // J. Atmos. Solar-Terr. Phys. V. 66. P. 1143-1149. 2004.

Pudovkin M. I., Anokhin S. G., and Starkov G. V. Permafrost Influence on the Total Ozone in the Atmosphere // Geomagnetism and Aeronomy. V. 44. No. 1. P. 87-92. 2004.

Chernouss S.A., Starkov G.V. Yevlashin L.S. World first complex optical instrumental observations of aurora in the Arctic in 1899-1900 // Ann. Geophys. V23. №5. P. 1523-1531. 2005.

Starkov G. V., Vorobjev V. G., and Feldstein Ya. I. Relative Position of the Regions of Auroral Precipitation and Discrete Auroras // Geomagnetism and Aeronomy. V. 45. No. 2. P. 170-180. 2005.

Vorobjev V. G. and Yagodkina O. I. Effect of Magnetic Activity on the Global Distribution of Auroral Precipitation Zones // Geomagnetism and Aeronomy. V. 45. No. 4. P. 438-444. 2005.

Starkov G. V, Pudovkin M. I., and Kornilova T. A. Auroral Fading Structure before Breakup: A Review // Geomagnetism and Aeronomy. V. 46. No. 1. P. 1-14. 2006.

Roldugin V. C., Vasiljev A. N. and Ostapenko A. A. Comparison of the Schumann resonance parameters in horizontal magnetic and electric fields according to observations on the Kola Peninsula // Radio Sci. 4142(2). RS2S07. doi:10.1029/2006RS003475. 2006.

Vorobjev V. G. and Yagodkina O. I. Influence of the Solar Wind Plasma Density on the Auroral Precipitation Characteristics // Geomagnetism and Aeronomy. V. 46. No. 1. P. 52-57. 2006.

Dashkevich Zh. V., Zverev V. L., and Ivanov V. E. Ratios of the I630.0/I427.8 and I557.7/I427.8 Emission Intensities in Auroras // Geomagnetism and Aeronomy. V. 46. No. 3. P. 366-371. 2006.

Roldugin V. K., Maltsev Yu. P., Ostapenko A. A., and Roldugin A. V. Generation of Long-Period Regular Pulsations in the Magnetosphere during SC // Geomagnetism and Aeronomy. V. 46. No. 4. P. 438-449. 2006.

Kornilova T. A., Kornilov I. A. and Kornilov O. I. Auroral Intensification Structure and Dynamics in the Double Oval: Substorm of December 26, 2000 // Geomagnetism and Aeronomy. V. 46. No. 4. P. 450-456. 2006.

Kozyreva O. V., Kleimenova N. G., Kornilova T. A., Kauriste K., Manninen J., and Ranta A. Unusual Spatial–Temporal Dynamics of Geomagnetic Disturbances during the Main Phase of the Extremely Strong Magnetic Storm of November 7–8, 2004 // Geomagnetism and Aeronomy. V. 46. No. 5. P. 580-592. 2006.

Hviuzova T. A., Tolochkina S. V. and Zverev V. L. Variations in the IMF Vertical Component in Isolated Solar Wind Streams // Geomagnetism and Aeronomy. V. 47. No. 2. P. 149-155. 2007.

Vorobjev V. G. and Yagodkina O. I. Auroral Precipitation Dynamics during Strong Magnetic Storms // Geomagnetism and Aeronomy. V. 47. No. 2. P. 185-192. 2007.

Vorobjev V. G., Yagodkina O. I., Starkov G. V. and Feldstein Ya. I. Features of the Planetary Distribution of Auroral Precipitation Characteristics during Substorms // Geomagnetism and Aeronomy. V. 47. No. 2. P. 193-204. 2007.

Zverev V. L. and Vorobjev V. G. Russian Studies of Antarctic Auroras: A Review // Geomagnetism and Aeronomy. V. 47. No. 2. P. 683-695. 2007.

Roldugin V.C. and Roldugin A. V. Pc5 pulsations on the ground, in the magnetosphere, and in the electron precipitation: Event of 19 January 2005 // J. Geophys. Res. V. 113, A04222, doi:10.1029/2007JA012553. 2008.

Vorobjev V.G., Yagodkina O.I. Empirical model of auroral precipitation power during substorms // J. Atm. Solar-Ter. Phys. V. 70. P. 654-662. 2008.

Kornilova T. A., Kornilov I. A., Kornilov O. I. Fine structure of breakup development inferred from satellite and ground-based observations // Ann. Geophys V. 26. P. 1141-1148. 2008.

Manninen J., Kleimenova N.G., Kozyreva O.V., Ranta A., Kauristie K., Mäkinen S. and Kornilova T. A. Ground-based observations during the period between two strong November 2004 storms attributed to steady magnetospheric convection // J. Geophys. Res. V. 113. A00A09. doi: 10.1029/2007JA012984. 2008.

Kornilov I.A., Antonova E.E., Kornilova T.A., Kornilov O.I. Fine structure of auroras during auroral breakup according to the ground based and satellite observation // Geomagnetism and Aeronomy. V. 48. No. 1. P. 7-20. 2008.

Zverev V. L. and Hviuzova T. A. Varitions in the polar precipitation equatorward boundary during the interaction between the Earth’s magnetosphere and solar wind streams from isolated solar sources // Geomagnetism and Aeronomy. V. 48. No. 1. P. 28-35. 2008.

Vorobjev V.G., Belakhovsky V.B., Yagodkina O.I., Roldugin V.K., Hairston M. R. Features of morning-time auroras during SC // Geomagnetism and Aeronomy. V. 48. No. 2. P. 154-164. 2008.

Belakhovsky V.B., Roldugin V.K. generation of Pc5 pulsations during the sign reversal of the IMF Bz component // Geomagnetism and Aeronomy. V. 48. No. 2. P. 180-186. 2008.

Vorobjev V.G., Kornilov I.A., Kornilova T.A., Yagodkina O.I., Sandholt P.I. Libbek B. Nighttime subvisual high latitude auroras // Geomagnetism and Aeronomy. V. 48. No. 5. P. 606-614. 2008.

Roldugin V.K., Beloglazov M.I. Schumann resonance amplitude during the Forbush effect // Geomagnetism and Aeronomy. V. 48. No. 6. P. 768-774. 2008.