Transient cusp ionospheric disturbances caused by a solar wind dynamic pressure enhancement

Mapping Intimacies ◽

10.5194/egusphere-egu21-634 ◽

2021 ◽

Author(s):

Jianjun Liu

Keyword(s):

Plasma Flow ◽

Dynamic Pressure ◽

Geomagnetic Disturbance ◽

Flow Reversal ◽

Drift Motion ◽

Zhongshan Station ◽

Shock Impingement ◽

Field Aligned Current ◽

Convection Patterns ◽

The Antarctic

Interplanetary (IP) shock driven sudden compression produces disturbances in the polar ionosphere. Various studies have investigated the effects of IP shock using imagers and radars. However, very few studies have reported the plasma flow reversal and a sudden vertical plasma drift motion following a CME driven IP shock. We report on the cusp ionospheric features following an IP shock impingement on 16 June 2012, using SuperDARN radar and digisonde from the Antarctic Zhongshan Station (ZHO). SuperDARN ZHO radar observed instant strong plasma flow reversal during the IP shock driven sudden impulse (SI) with a suppression in the number of backscatter echoes. Besides, we also report on a &#8220;Doppler Impulse&#8221; phenomenon, an instant and brief downward plasma motion, were observed by the digisonde in response to the SI and discuss the possible physical causes. Geomagnetic disturbance and convection patterns indicate the flow reversal was generated by the downward field-aligned current (FAC). We speculate that sudden enhancement in ionization associated with SI is responsible for generating the Doppler Impulse phenomenon.

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Marisediminicola antarctica gen. nov., sp. nov., an actinobacterium isolated from the Antarctic

INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY ◽

10.1099/ijs.0.018754-0 ◽

2010 ◽

Vol 60 (11) ◽

pp. 2535-2539 ◽

Cited By ~ 36

Author(s):

Hui-Rong Li ◽

Yong Yu ◽

Wei Luo ◽

Yin-Xin Zeng

Keyword(s):

Sequence Similarity ◽

Phylogenetic Analyses ◽

Intertidal Sediment ◽

Rrna Gene ◽

Optimum Growth ◽

Temperature Range ◽

Zhongshan Station ◽

Diamino Acid ◽

Ph Range ◽

The Antarctic

Strain ZS314T was isolated from a sandy intertidal sediment sample collected from the coastal area off the Chinese Antarctic Zhongshan Station, east Antarctica (6 ° 22′ 13″ S 7 ° 21′ 41″ E). The cells were Gram-positive, motile, short rods. The temperature range for growth was 0–26 °C and the pH for growth ranged from 5 to 10, with optimum growth occurring within the temperature range 18–23 °C and pH range 6.0–8.0. Growth occurred in the presence of 0–6 % (w/v) NaCl, with optimum growth occurring in the presence of 2–4 % (w/v) NaCl. Strain ZS314T had MK-10 as the major menaquinone and anteiso-C15 : 0, iso-C16 : 0 and anteiso-C17 : 0 as major fatty acids. The cell-wall peptidoglycan type was B2β with ornithine as the diagnostic diamino acid. The major polar lipids were diphosphatidylglycerol and phosphatidylglycerol. The genomic DNA G+C content was approximately 67 mol%. Phylogenetic analysis based on 16S rRNA gene sequence similarity showed that strain ZS314T represents a new lineage in the family Microbacteriaceae. On the basis of the phylogenetic analyses and phenotypic characteristics, a new genus, namely Marisediminicola gen. nov., is proposed, harbouring the novel species Marisediminicola antarctica sp. nov. with the type strain ZS314T (=DSM 22350T =CCTCC AB 209077T).

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Plasma convection in the magnetotail lobes: statistical results from Cluster EDI measurements

Annales Geophysicae ◽

10.5194/angeo-26-2371-2008 ◽

2008 ◽

Vol 26 (8) ◽

pp. 2371-2382 ◽

Cited By ~ 20

Author(s):

S. Haaland ◽

G. Paschmann ◽

M. Förster ◽

J. Quinn ◽

R. Torbert ◽

...

Keyword(s):

Magnetic Field ◽

Interplanetary Magnetic Field ◽

Geomagnetic Disturbance ◽

Plasma Convection ◽

Data Set ◽

Central Plasma ◽

Strong Convection ◽

Central Plasma Sheet ◽

Field Lines ◽

Convection Patterns

Abstract. A major part of the plasma in the Earth's magnetotail is populated through transport of plasma from the solar wind via the magnetotail lobes. In this paper, we present a statistical study of plasma convection in the lobes for different directions of the interplanetary magnetic field and for different geomagnetic disturbance levels. The data set used in this study consists of roughly 340 000 one-minute vector measurements of the plasma convection from the Cluster Electron Drift Instrument (EDI) obtained during the period February 2001 to June 2007. The results show that both convection magnitude and direction are largely controlled by the interplanetary magnetic field (IMF). For a southward IMF, there is a strong convection towards the central plasma sheet with convection velocities around 10 km s−1. During periods of northward IMF, the lobe convection is almost stagnant. A By dominated IMF causes a rotation of the convection patterns in the tail with an oppositely directed dawn-dusk component of the convection for the northern and southern lobe. Our results also show that there is an overall persistent duskward component, which is most likely a result of conductivity gradients in the footpoints of the magnetic field lines in the ionosphere.

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Spectral characteristics of protons in the Earth's plasmasheet: statistical results from Cluster CIS and RAPID

Annales Geophysicae ◽

10.5194/angeo-28-1483-2010 ◽

2010 ◽

Vol 28 (8) ◽

pp. 1483-1498 ◽

Cited By ~ 23

Author(s):

S. Haaland ◽

E. A. Kronberg ◽

P. W. Daly ◽

M. Fränz ◽

L. Degener ◽

...

Keyword(s):

Plasma Sheet ◽

Dynamic Pressure ◽

Spectral Characteristics ◽

Geomagnetic Disturbance ◽

Energy Spectra ◽

Spectral Slope ◽

Direct Response ◽

Characteristic Energy ◽

Local Time Dependence

Abstract. We present a study of the spectral characteristics of protons in the Earth's plasma sheet for various geomagnetic disturbance levels. The study is based on about 5400 h of data combined from the Cluster RAPID and CIS instruments obtained during the tail season (July–October). The overall proton spectral shape is generally that of a κ distribution, that is, resembling a Maxwellian at lower energies which smoothly merges into a power-law tail at higher energies. The actual spectral long-term slope depends on various magnetospheric driver parameters, but is on average around 3.5–4. During disturbed conditions, such as geomagnetic storm or substorm periods, a shift in the characteristic energy is observed. For two individual storms, we also found a hardening of the spectra. Unlike the electron spectra, we do not see any significant local time dependence in the spectral slope, but we find higher average ion fluxes in the dusk side. We also do not find any direct response in the energy spectra to changes in the interplanetary magnetic field or solar wind dynamic pressure. This suggests that energization of the ions are mainly due to internal processes in the plasma sheet.

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Crustal magnetic field advection on Mars from MAVEN observations

10.5194/egusphere-egu2020-4261 ◽

2020 ◽

Author(s):

Isabela de Oliveira ◽

Markus Fränz ◽

Adriane Franco ◽

Ezequiel Echer

Keyword(s):

Magnetic Field ◽

Plasma Flow ◽

Ionospheric Plasma ◽

Global Analysis ◽

Dynamic Pressure ◽

General Idea ◽

Mars Atmosphere ◽

Low Intensity ◽

Single Orbit ◽

Field Lines

The plasma environment of Mars is highly influenced by regions of remnant magnetism in the planetary crust, above which mini-magnetospheres are created. In this work, we study whether the ionospheric plasma flow can move crustal magnetic field lines, by the process of advection. According to this hypothesis, the magnetic field lines are dragged away in anti-solar direction, westward at dawn and eastward at dusk-side, due to the day-to-night flow of the ionospheric plasma. The altitude of interest is between 200 km and 1000 km, because the plasma flow velocity is significant in this region.MAVEN (Mars Atmosphere and Volatile EvolutioN) data is used for a direct comparison between magnetic field data and a crustal magnetic field model. The difference between the observed and the model field at each point of the grid is a measure of the sum of the induced day magnetic field and the possible displacement of the crustal field lines by advection. The results of the analysis show that, except for the lowest altitude range, minimum value of this difference is always observed for westward shift at dawn-side and eastward shift at dusk-side, in agreement with the expected motion of the crustal magnetic field lines.For a general idea of the relative forces between the moving plasma and the crustal fields, we use MAVEN data to analyze the pressures involved in the advection process. These are the dynamic pressure of the ionospheric plasma flow, the magnetic pressure of the field lines and the thermal pressure of the plasma related to the mini-magnetospheres. The balance between these quantities should dictate the occurrence of advection. This analysis suggests that advection could take place at low altitude (up to ~450 km) dawn-side regions above low intensity magnetic fields.Although the global analysis results showed agreement with our hypothesis, we could not observe evidence of advection from the local observations in order to unambiguously prove the occurrence of this process. Future works include the investigation of single orbit data in regions of low intensity magnetic field, especially at dawn-side, and also magnetohydrodynamic modeling of the process using the plasma conditions prevalent in the Martian ionosphere.

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Study of plasma flow reversal in the near-Earth plasma sheet using numerical computations

Earth Planets and Space ◽

10.1186/s40623-014-0147-1 ◽

2014 ◽

Vol 66 (1) ◽

Cited By ~ 1

Author(s):

Koji Kondoh ◽

Tohru Shimizu

Keyword(s):

Plasma Flow ◽

Plasma Sheet ◽

Flow Reversal ◽

Numerical Computations

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A wind effect of neutron component of cosmic rays at Antarctic station Mirny

Solar-Terrestrial Physics ◽

10.12737/19882 ◽

2016 ◽

Vol 2 (1) ◽

pp. 97-102

Author(s):

Павел Кобелев ◽

Pavel Kobelev ◽

Артем Абунин ◽

Artem Abunin ◽

Мария Абунина ◽

...

Keyword(s):

Wind Speed ◽

Dynamic Pressure ◽

Cosmic Ray ◽

Wind Effect ◽

High Mountain ◽

Hourly Data ◽

Neutron Component ◽

The Antarctic ◽

Local Weather ◽

Barometric Effect

The barometric effect of cosmic ray neutron component was estimated on the example of the Antarctic station Mirny. We used hourly data from continuous monitoring of neutron component and data from a local weather station for 2007–2014. Wind speed at the station Mirny reaches 20–40 m/s in winter that corresponds to the dynamic pressure 5–6 mbar and leads to a 5 % error in variations of neutron component because of dynamic effects in the atmosphere. The results can be applied to detectors located in high-latitude and high-mountain regions where the wind speed can be significant.

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Ionospheric electron content across the Antarctic continent

Antarctic Science ◽

10.1017/s0954102098000595 ◽

1998 ◽

Vol 10 (4) ◽

pp. 493-501

Author(s):

G. O. L. Jones ◽

L. Kersley ◽

J. A. T. Heaton ◽

L. Ciraolo ◽

P. Spalla

Keyword(s):

Standard Model ◽

Plasma Flow ◽

Electron Content ◽

Spatial Region ◽

Terra Nova Bay ◽

Ionospheric Electron Content ◽

Antarctic Continent ◽

Terra Nova ◽

The Antarctic ◽

First Time

Observations of satellite passes monitored at Halley and Terra Nova Bay have been combined to produce for the first time measurements of ionospheric electron content spanning the Antarctic continent. Results are presented from a sequence of four successive passes made during a period of some two hours that illustrate the development of the ionosphere over this wide spatial region. The observations are discussed in terms of the convective behaviour of the ionization, using results from the PACE radar and a standard model of the plasma flow.

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