Последние статьи в Annales Geophysicae

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Combined list of the recent articles of the journal Annales Geophysicae and the recent discussion forum Annales Geophysicae Discussions
Updated: 2 days 20 hours ago

Scaling laws in Hall-inertial range turbulence

Fri, 05/17/2019 - 16:58
Scaling laws in Hall-inertial range turbulence
Yasuhito Narita, Wolfgang Baumjohann, and Rudolf A. Treumann
Ann. Geophys. Discuss., https//doi.org/10.5194/angeo-2019-69,2019
Manuscript under review for ANGEO (discussion: open, 0 comments)
Scaling laws and energy spectra for the electric field, magnetic field, flow velocity, and density are theoretically derived for small-scale turbulence in space plasma on which the electrons behave as a fluid but the ions more as individual particles due to the difference in the mass (the Hall effect). Our spectrum model for small-scale turbulence can qualitatively explain the turbulence spectra measured in near-Earth space.
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Quasi-separatrix layers induced by ballooning instability in the near-Earth magnetotail

Tue, 05/14/2019 - 16:58
Quasi-separatrix layers induced by ballooning instability in the near-Earth magnetotail
Ping Zhu, Zechen Wang, Jun Chen, Xingting Yan, and Rui Liu
Ann. Geophys., 37, 325-335, https://doi.org/10.5194/angeo-37-325-2019, 2019
Our research explores a new method for identifying where and when the magnetic field lines in Earth's magnetotail may change its topology through the reconnection process, during which a sudden release of magnetic energy can lead to the brightening of aurora, a process called substorm. Traditionally, the magnetic reconnection was often interpreted using a two-dimensional model, which however does not capture the intrinsically three-dimensional nature of reconnection physics, as we have revealed.
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Phenomena preceding major earthquakes interconnected through a physical model

Fri, 05/10/2019 - 16:58
Phenomena preceding major earthquakes interconnected through a physical model
Panayiotis A. Varotsos, Nicholas V. Sarlis, and Efthimios S. Skordas
Ann. Geophys., 37, 315-324, https://doi.org/10.5194/angeo-37-315-2019, 2019
In this paper, we summarize the anomalous phenomena that were observed before the super-giant earthquake of magnitude 9.0 that occurred on 11 March 2011 in Japan. These phenomena have been detected by means of ground-based measurements and satellite data. We find that all these phenomena are in agreement with a condensed matter physical model that motivated in the 1980s a short-term earthquake prediction method based on the detection of precursory electric signals.
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Multi-point galactic cosmic rays measurements between 1 and 4.5 AU over a full Solar cycle

Fri, 05/10/2019 - 16:58
Multi-point galactic cosmic rays measurements between 1 and 4.5 AU over a full Solar cycle
Thomas Honig, Olivier G. Witasse, Hugh Evans, Petteri Nieminen, Erik Kuulkers, Matt G. G. T. Taylor, Bernd Heber, Jingnan Guo, and Beatriz Sánchez-Cano
Ann. Geophys. Discuss., https//doi.org/10.5194/angeo-2019-68,2019
Manuscript under review for ANGEO (discussion: open, 1 comment)
We have analysed data from radiation monitors on board different spacecraft such as Rosetta and Integral. From the data, we extracted the evolution of galactic cosmic rays as a function of time (over a full solar cycle) and position (from 1 to 4.5 astronomical units). As main results, we confirm the overall evolution (anti-correlation) of the fluxes with respect to the solar activity. We found a surprising result, which is a decrease of the flux of galactic cosmic rays around comet 67P.
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Signatures of red-shifted footpoints in the quiescent coronal loop system

Thu, 05/09/2019 - 16:58
Signatures of red-shifted footpoints in the quiescent coronal loop system
Yamini K. Rao, Abhishek K. Srivastava, Pradeep Kayshap, and Bhola N. Dwivedi
Ann. Geophys. Discuss., https//doi.org/10.5194/angeo-2019-66,2019
Manuscript under review for ANGEO (discussion: open, 0 comments)
Chromospheric flows are of significant importance to understand the mechanisms of transfer of plasma and energy from lower atmosphere of the Sun to the corona through transition region. We study the quiescent loop system in terms of Doppler velocities at the footpoints of individual loop strands to understand the heating mechanisms driving plasma flows in such loop system.
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Long Range Plasma Momentum Coupling by High Voltage Static Electric field and Deep Space Exploration

Thu, 05/09/2019 - 16:58
Long Range Plasma Momentum Coupling by High Voltage Static Electric field and Deep Space Exploration
Kokwei Chew, Xinyu Zhou, and Yian Lei
Ann. Geophys. Discuss., https//doi.org/10.5194/angeo-2019-41,2019
Manuscript under review for ANGEO (discussion: open, 0 comments)
By shooting away electrons from a spacecraft, it will deplete its surrounding electrons and create a large range of positively charged plasma, which will couple with an even larger range of the ambient plasma, and be accelerated or decelerated according to the relative speed between the craft and its ambience. A spacecraft can use the solar wind, artificial particle beam, or cosmic jet to achieve very high interstellar travelling velocity, or brake at the destination, with no propellant.
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Kinematic models of the interplanetary magnetic field

Wed, 05/08/2019 - 16:58
Kinematic models of the interplanetary magnetic field
Christoph Lhotka and Yasuhito Narita
Ann. Geophys., 37, 299-314, https://doi.org/10.5194/angeo-37-299-2019, 2019
The interplanetary magnetic field is a consequence of the solar magnetic field and the solar wind. Different magnetic field models exist in literature that allow us to better understand how the solar field extends throughout the solar system. We highlight different aspects of these different interplanetary magnetic field models and discuss possible applications. Verification of these models will become possible using data from the Parker Solar Probe and BepiColombo space mission.
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On modelling the kinematics and evolutionary properties of pressure pulse driven impulsive solar jets

Wed, 05/08/2019 - 16:58
On modelling the kinematics and evolutionary properties of pressure pulse driven impulsive solar jets
Balveer Singh, Kushagra Sharma, and Abhishek K. Srivastava
Ann. Geophys. Discuss., https//doi.org/10.5194/angeo-2019-67,2019
Manuscript under review for ANGEO (discussion: open, 0 comments)
Solar jets driven from the heating or pressure pulse at the footpoints in the photosphere transfer energy and mass in to the corona. These jets energize the coronal part of the atmosphere with the collimated plasma similar to the fluid filled in a pipe. Understanding the physical drivers of such jets is of great significance to study the plasma in confined magnetic fields. The modelled jets in our paper studies the evolution of chromospheric plasma and support many existing observations.
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Model of Propagation of VLF Beams in the Waveguide Earth-Ionosphere. Principles of Tensor Impedance Method in Multilayered Gyrotropic Waveguides

Tue, 05/07/2019 - 16:58
Model of Propagation of VLF Beams in the Waveguide Earth-Ionosphere. Principles of Tensor Impedance Method in Multilayered Gyrotropic Waveguides
Yuriy Rapoport, Vladimir Grimalsky, Victor Fedun, Oleksiy Agapitov, John Bonnell, Asen Grytsai, Gennadi Milinevsky, Alex Liashchuk, Alexander Rozhnoi, Maria Solovieva, and Andrey Gulin
Ann. Geophys. Discuss., https//doi.org/10.5194/angeo-2019-46,2019
Manuscript under review for ANGEO (discussion: open, 1 comment)
The paper treats analytically and numerically the new theoretical basis for ground-based and satellite monitoring the most powerful processes in the lower atmosphere/Earth (hurricanes, earthquakes etc.), solar wind-magnetosphere (magnetic storms) and ionosphere (lightning discharges/thunderstorms etc.). This can be provided by determination of phases and amplitudes of radio waves of kHz range in cavity Earth-Ionosphere. In perspective, the damage from the natural disasters can be decreased.
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Quarterdiurnal signature in sporadic E occurrence rates and comparison with neutral wind shear

Mon, 05/06/2019 - 16:58
Quarterdiurnal signature in sporadic E occurrence rates and comparison with neutral wind shear
Christoph Jacobi, Christina Arras, Christoph Geißler, and Friederike Lilienthal
Ann. Geophys., 37, 273-288, https://doi.org/10.5194/angeo-37-273-2019, 2019
Sporadic E (Es) layers in the Earth's ionosphere are produced by ion convergence due to vertical wind shear in the presence of a horizontal component of the Earth's magnetic field. We present analyses of the 6 h tidal signatures in ES occurrence rates derived from GPS radio observations. Times of maxima in ES agree well with those of negative wind shear obtained from radar observation. The global distribution of ES amplitudes agrees with wind shear amplitudes from numerical modeling.
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Magnetic dipolarizations inside geosynchronous orbit with tailward ion flows

Mon, 05/06/2019 - 16:58
Magnetic dipolarizations inside geosynchronous orbit with tailward ion flows
Xiaoying Sun, Weining William Liu, and Suping Duan
Ann. Geophys., 37, 289-297, https://doi.org/10.5194/angeo-37-289-2019, 2019

Electromagnetic field and plasma data from the Time History of Events and Macroscale Interactions during Substorms (THEMIS) near-Earth probes are used to investigate magnetic dipolarizations inside geosynchronous orbit on 27 August 2014 during an intense substorm with AEmax∼1000 nT. THEMIS-D (TH-D) was located inside geosynchronous orbit around midnight in the interval from 09:25 to 09:55 UT. During this period, two distinct magnetic dipolarizations with tailward ion flows are observed by TH-D. The first one is indicated by the magnetic elevation angle increase from 15 to 25∘ around 09:30:40 UT. The tailward perpendicular velocity is V⊥x∼-50 km s−1. The second one is presented by the elevation angle increase from 25 to 45∘ around 09:36 UT, and the tailward perpendicular velocity is V⊥x∼-70 km s−1. These two significant dipolarizations are accompanied with the sharp increase in the energy flux of energetic electron inside geosynchronous orbit. After a 5 min expansion of the near-Earth plasma sheet (NEPS), THEMIS-E (TH-E) located outside geosynchronous orbit also detected this tailward expanding plasma sheet with ion flows of −150 km s−1. The dipolarization propagates tailward with a speed of −47 km s−1 along a 2.2 RE distance in the X direction between TH-D and TH-E within 5 min. These dipolarizations with tailward ion flows observed inside geosynchronous orbit indicate a new energy transfer path in the inner magnetosphere during substorms.

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Jets in the Magnetosheath: IMF Control of Where They Occur

Mon, 05/06/2019 - 16:58
Jets in the Magnetosheath: IMF Control of Where They Occur
Laura Vuorinen, Heli Hietala, and Ferdinand Plaschke
Ann. Geophys. Discuss., https//doi.org/10.5194/angeo-2019-65,2019
Manuscript under review for ANGEO (discussion: open, 0 comments)
Before the solar wind encounters the Earth's magnetic field, it is first slowed down and deflected by the Earth's bow shock. We find that downstream of the bow shock regions where the shock normal and the solar wind magnetic field are almost parallel and the shock is more rippled, plasma jets with high earthward velocities are observed significantly more often than elsewhere downstream of the shock. Our results help us forecast the occurrence of these jets and their effects on Earth.
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Semimonthly oscillation observed in the start time of equatorial Spread-F

Thu, 05/02/2019 - 16:58
Semimonthly oscillation observed in the start time of equatorial Spread-F
Igo Paulino, Ana Roberta Paulino, Ricardo Yvan de la Cruz Cueva, Ebenezer Agyei-Yeboah, Ricardo Arlen Buriti, Hisao Takahashi, Cristiano Max Wrasse, and Amauri Fragoso de Medeiros
Ann. Geophys. Discuss., https//doi.org/10.5194/angeo-2019-62,2019
Manuscript under review for ANGEO (discussion: open, 0 comments)
In this paper, an extensive study has been done in order to investigate periodic oscillation in the start time of spread-F observed over Brazil. Using OI6300 airglow images and range time integration from a backscatter coherent radar, it was possible to detect semimonthly oscillations in the start time of Equatorial Plasma Bubbles, Plumes and Bottom-type spread-F. The knowledge of this oscillation must be important to understand the dynamics of the day-to-day variability of spread-F.
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Comparing high-latitude thermospheric winds from FPI and CHAMP accelerometer measurements

Mon, 04/29/2019 - 16:58
Comparing high-latitude thermospheric winds from FPI and CHAMP accelerometer measurements
Anasuya Aruliah, Matthias Förster, Rosie Hood, Ian McWhirter, and Eelco Doornbos
Ann. Geophys. Discuss., https//doi.org/10.5194/angeo-2019-57,2019
Manuscript under review for ANGEO (discussion: open, 1 comment)
Winds near the top of the atmosphere are expected to be the same at all heights for a given location. This is due to assuming high viscosity in rarefied gases. However, wind measurements from satellite drag at 350–400 km altitude are found to be up to 2 times larger than optical measurements at ~ 240 km. Satellites provide global measurements, and ground-based optical instruments provide long-term monitoring at single sites. So we must understand this inconsistency for correct physics prediction.
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Identifying possible Stratification phenomenon in ionospheric F2 Layer using the data observed by the Demeter satellite: Method and Results

Mon, 04/29/2019 - 16:58
Identifying possible Stratification phenomenon in ionospheric F2 Layer using the data observed by the Demeter satellite: Method and Results
Xiuying Wang, Dehe Yang, Dapeng Liu, and Wei Chu
Ann. Geophys. Discuss., https//doi.org/10.5194/angeo-2019-55,2019
Manuscript under review for ANGEO (discussion: open, 2 comments)
To check the difference between data observed at different altitudes of the Demeter satellite, a statistical method is adopted to evaluate whether data difference is caused by normal data fluctuation or by altitude adjustment. Based on the method, the in situ electron density data at higher altitude are found to be greater than that at lower altitude. We speculate this phenomenon is caused by stratification above F2 peak region. The proposed method is useful when comparing fluctuated data.
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A case study of the large-scale traveling ionospheric disturbances in the East Asian sector during the 2015 St. Patrick’s Day geomagnetic storm

Mon, 04/29/2019 - 16:58
A case study of the large-scale traveling ionospheric disturbances in the East Asian sector during the 2015 St. Patrick’s Day geomagnetic storm
Jing Liu, Dong-He Zhang, Anthea J. Coster, Shun-Rong Zhang, Guan-Yi Ma, Yong-Qiang Hao, and Zuo Xiao
Ann. Geophys. Discuss., https//doi.org/10.5194/angeo-2019-63,2019
Manuscript under review for ANGEO (discussion: open, 1 comment)

This study gives the first observation of the large-scale traveling ionospheric disturbances (LSTIDs) in the East Asian sector during the 2015 St. Patrick’s Day (March 17, 2015) geomagnetic storm. For the first time, 3 dense networks of GPS receivers in China and Japan are combined together to obtain the 2-dimensional (2D) vertical total electron content (VTEC) perturbation maps in a wider longitudinal range than previous works in this region. Results show that a negative LSTID spanning at least 60° in longitude (80° E–140° E) occurs and propagating from high to lower latitudes around 09:40–11:20 UT. It is followed by a positive LSTID which shows a tendency of dissipation starting from the East side. The manifestation of the 2D VTEC perturbation maps is in good agreement with the recordings from 2 high-frequency Doppler shift stations and the iso-frequency lines from 8 ionosondes. Then, the propagation parameters of the LSTIDs are estimated by applying least square fitting methods to the distinct structures in the 2D VTEC perturbation plots. In general, the propagation parameters are observably longitudinal dependent. For example, the propagation direction is almost due southward between 105° E–115° E, while it is slightly South by West/East in the West/East side of this region. This feature is probably related to the regional geomagnetic declination. The mean values of the period, trough velocity (Vt), crest velocity (Vc), and wavelength of the wavelike LSTIDs in the studied longitudinal bands are 74.8 ± 1.4 minutes, 578 ± 16 m/s, 617 ± 23 m/s, and 2691 ± 80 km, respectively. Finally, using the VTEC map data from the Madrigal database of the MIT Haystack Observatory, the characteristics of the ionospheric disturbances over the European sector (30° N–70° N, 10° E–20° E) are also studied. The results are very different from those in the East Asian sector in parameters like the occurrence time, oscillation period, and propagation velocities.

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Validation and application of optimal ionospheric shell height model for single-site estimation of total electron content

Fri, 04/26/2019 - 16:58
Validation and application of optimal ionospheric shell height model for single-site estimation of total electron content
Jiaqi Zhao and Chen Zhou
Ann. Geophys., 37, 263-271, https://doi.org/10.5194/angeo-37-263-2019, 2019

We recently proposed a method to establish an optimal ionospheric shell height model based on the international GNSS service (IGS) station data and the differential code bias (DCB) provided by the Center for Orbit Determination in Europe (CODE) during the time from 2003 to 2013. This method is very promising for DCB and accurate total electron content (TEC) estimation by comparing to the traditional fixed shell height method. However, this method is basically feasible only for IGS stations. In this study, we investigate how to apply the optimal ionospheric shell height derived from IGS station to non-IGS stations or isolated GNSS receivers. The intuitive and practical method to estimate TEC of non-IGS stations is based on optimal ionospheric shell height derived from nearby IGS stations. To validate this method, we selected two dense networks of IGS stations located in regions in the US and Europe. Two optimal ionospheric shell height models are established by two reference stations, namely GOLD and PTBB, which are located at the approximate center of two selected regions. The predicted daily optimal ionospheric shell heights by the two models are applied to other IGS stations around these two reference stations. Daily DCBs are calculated according to these two optimal shell heights and compared to respective DCBs released by CODE. The validation results of this method are as follows. (1) Optimal ionospheric shell height calculated by IGS stations can be applied to its nearby non-IGS stations or isolated GNSS receivers for accurate TEC estimation. (2) As the distance away from the reference IGS station becomes larger, the DCB estimation error becomes larger. The relation between the DCB estimation error and the distance is generally linear.

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Characteristics of ionospheric irregularities near the northern equatorial anomaly crest

Fri, 04/26/2019 - 16:58
Characteristics of ionospheric irregularities near the northern equatorial anomaly crest
Jinghua Li, Guanyi Ma, Klemens Hocke, Qingtao Wan, Jiangtao Fan, and Xiaolan Wang
Ann. Geophys. Discuss., https//doi.org/10.5194/angeo-2019-64,2019
Manuscript under review for ANGEO (discussion: open, 0 comments)
Local occurrence rate (LOR) is defined to clarify the characteristics of ionospheric irregularities together with monthly occurrence rate (MOR) at 20–29° N in solar minimum, medium and maximum years of 2008, 2003 and 2014. MOR of irregularities in May/June is larger than that in equinoxes, which is different with the equatorial plasma bubbles. LOR shows that the irregularities at 26–29° N in May/June are more frequently happened and have smaller spatiotemporal scales than those at lower latitudes.
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Magnetic local time asymmetries in electron and proton precipitation with and without substorm activity

Wed, 04/24/2019 - 16:58
Magnetic local time asymmetries in electron and proton precipitation with and without substorm activity
Olesya Yakovchuk and Jan Maik Wissing
Ann. Geophys. Discuss., https//doi.org/10.5194/angeo-2019-49,2019
Manuscript under review for ANGEO (discussion: open, 0 comments)
We present the MLT-distribution of energetic particle precipitation into the ionosphere in combination with different substorm activities as well as MLT-dependent trapped plasmaspheric particle flux. MLT dependence can be assigned to different particle sources and energy-specific drifts. The maximum flux asymmetry ratio depends on particle energy, but not necessarily on geomagnetic disturbance. Substorms increase particle precipitation during night (factor 2–4) but may reduce it during day.
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Hybrid-Vlasov modelling of nightside auroral proton precipitation during southward interplanetary magnetic field conditions

Wed, 04/24/2019 - 16:58
Hybrid-Vlasov modelling of nightside auroral proton precipitation during southward interplanetary magnetic field conditions
Maxime Grandin, Markus Battarbee, Adnane Osmane, Urs Ganse, Yann Pfau-Kempf, Lucile Turc, Thiago Brito, Tuomas Koskela, Maxime Dubart, and Minna Palmroth
Ann. Geophys. Discuss., https//doi.org/10.5194/angeo-2019-59,2019
Manuscript under review for ANGEO (discussion: open, 0 comments)
When the terrestrial magnetic field is disturbed, particles from the near-Earth space can precipitate into the upper atmosphere. This work presents for the first time numerical simulations of proton precipitation in the energy range associated with the production of aurora (~ 1–30 keV) using a global kinetic model of the near-Earth space: Vlasiator. We find that nightside proton precipitation can be regulated by the transition region between stretched and dipolar geomagnetic field lines.
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