scholarly journals Geomagnetic Activity at Lampedusa Island: Characterization and Comparison with the Other Italian Observatories, Also in Response to Space Weather Events

2021 ◽  
Vol 13 (16) ◽  
pp. 3111
Author(s):  
Domenico Di Mauro ◽  
Mauro Regi ◽  
Stefania Lepidi ◽  
Alfredo Del Corpo ◽  
Guido Dominici ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Space Weather ◽  
Current System ◽  
Low Frequency ◽  
The Other ◽  
Quality Data ◽  
Individual Response ◽  
High Quality ◽  
Superposed Epoch Analysis ◽  
Weather Events

Regular automatic recordings of the time series of the magnetic field, together with routine manual absolute measurements for establishing dynamic baselines at Lampedusa Island—south of Sicily—Italy (geographic coordinates 35∘31’N; 12∘32’E, altitude 33 m a.s.l.), show a signature of very low electromagnetic noise. The observatory (provisional IAGA code: LMP) lays inside a restricted and remote wildlife reserve, far away from the built-up and active areas of the island, which at present is the southernmost location of the European territory for such observations. The availability of high-quality data from such site, whose survey started in 2005, is valuable for filling the spatial gap due to the lack of observatories in the whole south Mediterranean and North African sectors. We compare observations at Lampedusa, in both time and frequency domains, with those at the other Italian observatories (Castello Tesino and Duronia-L’Aquila), operating since the 1960s of last century, allowing us to report even the secular variation. Using data recorded in the last few years, we investigate higher frequency variations (from diurnal to Pc3-4 pulsations) in order to magnetically characterize the Italian territory and the local response to external forcing. In particular, we present a characterization in terms of diurnal variation and its seasonal dependence for the three observatories. This latter feature is in good agreement with a geomagnetic Sq-model, leading us to speculate about the position of the north Sq-current system vortex and its seasonal displacement with respect to the geographic positions of the observatories. We also study the geomagnetic individual response to intense space weather events by performing Superposed Epoch Analysis (SEA), with an ad-hoc significance test. Magnetic responses in the Ultra Low Frequency range (ULF) from spectral, local Signal-to-Noise Ratio (SNR) analyses under different local time, and polarization rates are computed. These latter studies lead us to search for possible signatures of magnetic field line resonances during intense space weather events, using cross-phase multi-observatory analysis, revealing the promising detection capability of such technique even at low latitudes. The geomagnetic observatories prove to be important points of observation for space weather events occurring at different spatial and time scales, originating in both upstream and ionospheric regions, here analyzed by several well-established methodologies and techniques. The quiet environmental site of LMP, providing high-quality geomagnetic data, allows us such investigations even at inner Earth’s magnetospheric shell.

scholarly journals The effect of the Solar wind on low-frequency observations of pulsars

2017 ◽  
Vol 13 (S337) ◽  
pp. 279-282 ◽  
Author(s):  
C. Tiburzi ◽  
J. P. W. Verbiest
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Interplanetary Magnetic Field ◽  
Electron Density ◽  
Low Frequency ◽  
Quality Data ◽  
High Quality ◽  
High Quality Data ◽  
Pulsar Radiation ◽  
First Results

AbstractWe operate the six German stations of the LOw Frequency ARray as standalone telescopes to observe more than 100 pulsars every week. To date, we have collected almost four years of high-quality data at an unprecedented weekly cadence. This allows us to perform a wide variety of analyses aimed at characterising the magnetoionic plasma crossed by pulsar radiation. In particular, our studies are focused on electron density variations in the interstellar and interplanetary media, the Galactic and interplanetary magnetic field, scintillation, and extreme scattering events. Here we report the first results from our Solar wind monitoring campaign.

Magnetic Field Variations in Alaska: Recording Space Weather Events on Seismic Stations in Alaska

2020 ◽  
Vol 110 (5) ◽  
pp. 2530-2540 ◽  
Author(s):  
Adam T. Ringler ◽  
Robert E. Anthony ◽  
David C. Wilson ◽  
Abram C. Claycomb ◽  
John Spritzer
Keyword(s):  
Magnetic Field ◽  
Ground Motion ◽  
Space Weather ◽  
Vertical Component ◽  
Environmental Data ◽  
Magnetic Data ◽  
Seismic Stations ◽  
Weather Events ◽  
S Period ◽  
Magnetic Field Variations

ABSTRACT Seismometers are highly sensitive instruments to not only ground motion but also many other nonseismic noise sources (e.g., temperature, pressure, and magnetic field variations). We show that the Alaska component of the Transportable Array is particularly susceptible to recording magnetic storms and other space weather events because the sensors used in this network are unshielded and magnetic flux variations are stronger at higher latitudes. We also show that vertical-component seismic records across Alaska are directly recording magnetic field variations between 40 and 800 s period as opposed to actual ground motion during geomagnetic events with sensitivities ranging from 0.004 to 0.48  (m/s2)/T. These sensitivities were found on a day where the root mean square variation in the magnetic field was 225 nT. Using a method developed by Forbriger (2007, his section 3.1), we show that improving vertical seismic resolution of an unshielded sensor by as much as 10 dB in the 100–400 s period band using magnetic data from a collocated three-component magnetometer is possible. However, due to large spatial variations in Earth’s magnetic field, this methodology becomes increasingly ineffective as the distance between the seismometer and magnetometer increases (no more than 200 km separation). A potential solution to this issue may be to incorporate relatively low-cost magnetometers as an additional environmental data stream at high-latitude seismic stations. We demonstrate that the Bartington Mag-690 sensors currently deployed at Global Seismographic Network sites are not only acceptable for performing corrections to seismic data, but are also capable of recording many magnetic field signals with similar signal-to-noise ratios, in the 20–1000 s period band, as the observatory grade magnetometers operated by the U.S. Geological Survey Geomagnetism Program. This approach would densify magnetic field observations and could also contribute to space weather monitoring by supplementing highly calibrated magnetometers with additional sensors.

Severe Space Weather: Simulations of Scaled-Up Storms

2020 ◽  
Author(s):  
Joachim Raeder ◽  
Beket Tulegenov ◽  
William Douglas Cramer ◽  
Kai Germaschewswski ◽  
Banafsheh Ferdousi ◽  
...  
Keyword(s):  
Solar Wind ◽  
Space Weather ◽  
Extreme Events ◽  
The Other ◽  
Polar Cap ◽  
Quiet Sun ◽  
Other Hand ◽  
Weather Events ◽  
The One ◽  
Extreme Space Weather Events

<p>Extreme space weather events are extremely rare, but pose a significant threat to our infrastructure. The one known event of such kind was the Carrington storm of 1859, but it was not well documented; in particular the solar wind and IMF conditions that caused it remain guesses. On the other hand, the STEREO-A observations of July 23, 2012 showed solar wind and IMF parameters that are most likely comparable to those of the Carrington event, and remind us that such extreme events are very well possible even during times of a quiet sun. Here, we use OpenGGCM simulations of such events to assess the effects of such solar wind and IMF on the magnetosphere. Precious work has shown that during the much more benign Halloween storm the nose of the magnetopause was as close as 4.9 RE, with an accordingly large polar cap. We will present simulations of a sequence of scaled-up storms with increasingly larger driving and demonstrate the further expansion of the polar cap, intensity of plasma injections, and the eventual saturation. In addition, we will show how the ionosphere potential penetrates to lower latitudes and affects the ionosphere and thermosphere at mid latitudes when the solar wind drivers become extreme.</p>

Successive Magnetic Transitions on Single Crystal Cu3(OH)4SO4

2011 ◽  
Vol 170 ◽  
pp. 194-197
Author(s):  
Shigeo Hara ◽  
Hirohiko Sato
Keyword(s):  
Magnetic Field ◽  
Single Crystal ◽  
Single Crystals ◽  
Field Dependence ◽  
Easy Axis ◽  
The Other ◽  
Magnetic Transitions ◽  
Copper Hydroxide ◽  
High Quality ◽  
Measured Field

Cu3(OH)4SO4, a parallel Cu (S = 1/2) triple chain system, is an interesting magnet because an idle-spin state is expected on the central chain. We have succeeded in growing high-quality single crystals of Cu3SO4(OH)4 by a hydrothermal method from copper sulfate and copper hydroxide. We measured field dependence of the magnetization on a single crystal under various directions of magnetic field up to 7 T. We found a clear magnetic anisotropy and confirmed that the existence of the easy axis lies in the ac plane. Under magnetic fields parallel to the c-axis and the a-axis at 2.5 K, we observed field-induced successive magnetic transitions. In the case of B//c, two anomalies of the magnetization are observed at 0.9 and 1.7 T, On the other hand, there are broad anomalies in the magnetization at 3.7 and 5.6 T in the case of B//a.

scholarly journals Challenges and Strategic Research Plans for Earth and Heliosphere: Research Infrastructures, Projects and Initiatives

2017 ◽  
Vol 13 (S335) ◽  
pp. 219-225
Author(s):  
Ingrid Mann ◽  
Kirsti Kauristi ◽  
Ruth Bamford ◽  
Ian McCrea ◽  
Joeran Moen ◽  
...  
Keyword(s):  
Space Weather ◽  
Model Development ◽  
Quality Data ◽  
High Quality ◽  
High Quality Data ◽  
Strategic Research ◽  
Research Infrastructures ◽  
Infrastructure Project ◽  
Open Issues ◽  
Weather Research

AbstractWe describe existing research infrastructures relevant for space weather and open issues of space weather research including the need for sustainable observation networks and for high-quality data products as basis for model development. The local relevance in Europe for studies of the ionosphere at high latitude is described. We propose as possible a way forward to sustain space weather research in Europe to establish a European research infrastructure project for space weather research and observations.

scholarly journals Study of Interplanetary and Geomagnetic Response of Filament Associated CMEs

2018 ◽  
Vol 13 (S340) ◽  
pp. 83-84
Author(s):  
Kunjal Dave ◽  
Wageesh Mishra ◽  
Nandita Srivastava ◽  
R. M. Jadhav
Keyword(s):  
Magnetic Field ◽  
Geomagnetic Activity ◽  
Space Weather ◽  
Coronal Mass Ejections ◽  
The Sun ◽  
The Earth ◽  
Weather Events ◽  
Terrestrial Magnetic Field

AbstractIt has been established that Coronal Mass Ejections (CMEs) may have significant impact on terrestrial magnetic field and lead to space weather events. In the present study, we selected several CMEs which are associated with filament eruptions on the Sun. We attempt to identify the presence of filament material within ICME at 1AU. We discuss how different ICMEs associated with filaments lead to moderate or major geomagnetic activity on their arrival at the Earth. Our study also highlights the difficulties in identifying the filament material at 1AU within isolated and in interacting CMEs.

Local magnetic field distribution in polycrystalline YBa2Cu3O7 and its influence on bulk critical currents

1991 ◽  
Vol 6 (6) ◽  
pp. 1135-1147 ◽  
Author(s):  
Thomas R. Askew ◽  
Richard B. Flippen ◽  
Kevin J. Leary ◽  
Milind N. Kunchur
Keyword(s):  
Magnetic Field ◽  
Simple Model ◽  
Critical Current Density ◽  
Field Distribution ◽  
Critical Currents ◽  
The Other ◽  
Magnetic Field Distribution ◽  
Local Magnetic Field ◽  
Transport Critical Current Density ◽  
High Quality

The transport critical current density Jc has been measured in high quality polycrystalline YBa2Cu3O7 samples made from extruded preforms. The hysteretic response of Jc to applied magnetic fields was studied as a function of temperature (77–87 K) and sample morphology for various field sweeps in the 0–5 KOe range. A variety of samples show a basic Jc ∼ H−n behavior where n depends on temperature, but is independent of the other variables. A simple model of the local magnetic field distribution is presented and compared to the data, and the theoretical implications of the power law behavior are considered.

SPIN–LATTICE INTERACTION EXPERIMENTS ON COLOR CENTERS IN QUARTZ

1964 ◽  
Vol 42 (4) ◽  
pp. 595-607 ◽  
Author(s):  
A. L. Taylor ◽  
G. W. Farnell
Keyword(s):  
Magnetic Field ◽  
Dielectric Loss ◽  
Low Frequency ◽  
The Other ◽  
Color Centers ◽  
Resonance Signal ◽  
Spin Lattice ◽  
Resonance Frequencies ◽  
Spin Resonance ◽  
The Magnetic Field

The paramagnetism of the color centers in smoky quartz is caused by the electron which is missing from a nonbonding oxygen orbital near an aluminum impurity. The effects produced by externally introduced microwave phonons on the spin-resonance signal from these color centers have been studied in detail as a function of the relative phonon and spin-resonance frequencies, the phonon power, the spectrometer power, the magnetic field angle, and the phonon polarization. As has been noted previously, these interactions do not conform with those observed in other paramagnetic crystals. Effects of an applied electric field on the resonance lines and various further experiments on the color centers in smoky quartz are reported; two in particular suggest that the "hole", the missing electron, makes thermally excited transitions between two different sites adjacent to a given impurity atom. One of the experiments is a measurement of the cross relaxation which takes place between the various lines of the spectrum, while the other is a measurement of the low-frequency dielectric loss found at liquid helium temperatures. An attempt is made to discuss the spin-phonon results in terms of such transitions for the holes.

Orientation of Prominence Microstructure Relative to the Direction of the Magnetic Field

1979 ◽  
Vol 44 ◽  
pp. 97-101
Author(s):  
O. Engvold ◽  
J.L. Leroy
Keyword(s):  
Magnetic Field ◽  
The Other ◽  
Optical Observations ◽  
High Quality ◽  
Hanle Effect ◽  
Other Hand ◽  
Solar Prominences ◽  
The Magnetic Field ◽  
Good Agreement ◽  
Field Strengths

Recent measurements of the polarization of the Hel D3 line (λ5876Å) in solar prominences (Hanle effect) have been used to infer new data about prominence magnetic field (Leroy 1977, Leroy et al. 1977, Sahal-Brèchot et al. 1977). The derived field strengths are in good agreement with previous magnetographic measurements obtained at several observatories in USA (Rust 1972). Using the Hanle effect also gives the direction of the magnetic field, which is a crusial parameter in theories of prominences (Kippenhahn and Schlüter 1957, Anzer 1968, Malville 1976). Some theories require a horizontal oriented magnetic field in the prominences. High quality optical observations, on the other hand, resolve predominantly vertically oriented prominence microstructure (Dunn 1972, Engvold 1976).

A Coupled System of a Magnet and Magnetic Fluid in a U-Tube under Reciprocating Traveling Magnetic Field

2010 ◽  
Vol 670 ◽  
pp. 207-214 ◽  
Author(s):  
Yasushi Ido ◽  
Koichi Hayashi ◽  
Takahiro Kunitomo
Keyword(s):  
Magnetic Field ◽  
Magnetic Fluid ◽  
Vibration Mode ◽  
Low Frequency ◽  
Coupled System ◽  
The Other ◽  
Reciprocating Motion ◽  
Vibration Properties ◽  
Short Cylinder ◽  
Traveling Magnetic Field

A coupled system of a magnet and magnetic fluid is used as a piston in a U-tube. Applying reciprocating travelling magnetic field produces reciprocating motion of the coupled system. In this study, vibration properties of the coupled system are investigated experimentally. Three types of vibration mode of the coupled system appear and the mode depends on the frequency and intensity of travelling magnetic field and the shape of the magnet. Basically the coupled system follows the travelling magnetic field in the range of low frequency, while the system cannot follow the travelling field when the frequency of the travelling magnetic field is high. However, when the magnet is sphere or short cylinder, the other type of vibration appears in the range of low frequency and the coupled system intermittently tracks the travelling magnetic field.

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