P II – 1–3 Geomagnetic storm, strong solar wind and stream interaction region affect for cardiovascular system

Author(s):  
Deivydas Kiznys ◽  
Jonė Venclovienė
2009 ◽  
Vol 114 (A12) ◽  
pp. n/a-n/a ◽  
Author(s):  
D. Pokhotelov ◽  
C. N. Mitchell ◽  
P. T. Jayachandran ◽  
J. W. MacDougall ◽  
M. H. Denton

2015 ◽  
Vol 4 (1) ◽  
pp. 1-18 ◽  
Author(s):  
M. Díaz-Michelena ◽  
R. Sanz ◽  
M. F. Cerdán ◽  
A. B. Fernández

Abstract. MOURA instrument is a three-axis magnetometer and gradiometer designed and developed for Mars MetNet Precursor mission. The initial scientific goal of the instrument is to measure the local magnetic field in the surroundings of the lander i.e. to characterize the magnetic environment generated by the remanent magnetization of the crust and the superimposed daily variations of the field produced either by the solar wind incidence or by the thermomagnetic variations. Therefore, the qualification model (QM) will be tested in representative scenarios like magnetic surveys on terrestrial analogues of Mars and monitoring solar events, with the aim to achieve some experience prior to the arrival to Mars. In this work, we present a practical first approach for calibration of the instrument in the laboratory; a finer correction after the comparison of MOURA data with those of a reference magnetometer located in San Pablo de los Montes (SPT) INTERMAGNET Observatory; and a comparative recording of a geomagnetic storm as a demonstration of the compliance of the instrument capabilities with the scientific objectives.


2017 ◽  
Vol 35 (6) ◽  
pp. 1309-1326 ◽  
Author(s):  
Patricia Mara de Siqueira Negreti ◽  
Eurico Rodrigues de Paula ◽  
Claudia Maria Nicoli Candido

Abstract. Total electron content (TEC) is extensively used to monitor the ionospheric behavior under geomagnetically quiet and disturbed conditions. This subject is of greatest importance for space weather applications. Under disturbed conditions the two main sources of electric fields, which are responsible for changes in the plasma drifts and for current perturbations, are the short-lived prompt penetration electric fields (PPEFs) and the longer-lasting ionospheric disturbance dynamo (DD) electric fields. Both mechanisms modulate the TEC around the globe and the equatorial ionization anomaly (EIA) at low latitudes. In this work we computed vertical absolute TEC over the low latitude of South America. The analysis was performed considering HILDCAA (high-intensity, long-duration, continuous auroral electrojet (AE) activity) events and geomagnetic storms. The characteristics of storm-time TEC and HILDCAA-associated TEC will be presented and discussed. For both case studies presented in this work (March and August 2013) the HILDCAA event follows a geomagnetic storm, and then a global scenario of geomagnetic disturbances will be discussed. Solar wind parameters, geomagnetic indices, O ∕ N2 ratios retrieved by GUVI instrument onboard the TIMED satellite and TEC observations will be analyzed and discussed. Data from the RBMC/IBGE (Brazil) and IGS GNSS networks were used to calculate TEC over South America. We show that a HILDCAA event may generate larger TEC differences compared to the TEC observed during the main phase of the precedent geomagnetic storm; thus, a HILDCAA event may be more effective for ionospheric response in comparison to moderate geomagnetic storms, considering the seasonal conditions. During the August HILDCAA event, TEC enhancements from  ∼  25 to 80 % (compared to quiet time) were observed. These enhancements are much higher than the quiet-time variability observed in the ionosphere. We show that ionosphere is quite sensitive to solar wind forcing and considering the events studied here, this was the most important source of ionospheric responses. Furthermore, the most important source of TEC changes were the long-lasting PPEFs observed on August 2013, during the HILDCAA event. The importance of this study relies on the peculiarity of the region analyzed characterized by high declination angle and ionospheric gradients which are responsible for creating a complex response during disturbed periods.


2006 ◽  
Vol 24 (1) ◽  
pp. 407-414 ◽  
Author(s):  
S. Simon ◽  
T. Bagdonat ◽  
U. Motschmann ◽  
K.-H. Glassmeier

Abstract. The interaction of a magnetized asteroid with the solar wind is studied by using a three-dimensional hybrid simulation code (fluid electrons, kinetic ions). When the obstacle's intrinsic magnetic moment is sufficiently strong, the interaction region develops signs of magnetospheric structures. On the one hand, an area from which the solar wind is excluded forms downstream of the obstacle. On the other hand, the interaction region is surrounded by a boundary layer which indicates the presence of a bow shock. By analyzing the trajectories of individual ions, it is demonstrated that kinetic effects have global consequences for the structure of the interaction region.


2019 ◽  
Vol 622 ◽  
pp. A28 ◽  
Author(s):  
N. Wijsen ◽  
A. Aran ◽  
J. Pomoell ◽  
S. Poedts

Aims. We introduce a new solar energetic particle (SEP) transport code that aims at studying the effects of different background solar wind configurations on SEP events. In this work, we focus on the influence of varying solar wind velocities on the adiabatic energy changes of SEPs and study how a non-Parker background solar wind can trap particles temporarily at small heliocentric radial distances (≲1.5 AU) thereby influencing the cross-field diffusion of SEPs in the interplanetary space. Methods. Our particle transport code computes particle distributions in the heliosphere by solving the focused transport equation (FTE) in a stochastic manner. Particles are propagated in a solar wind generated by the newly developed data-driven heliospheric model, EUHFORIA. In this work, we solve the FTE, including all solar wind effects, cross-field diffusion, and magnetic-field gradient and curvature drifts. As initial conditions, we assume a delta injection of 4 MeV protons, spread uniformly over a selected region at the inner boundary of the model. To verify the model, we first propagate particles in nominal undisturbed fast and slow solar winds. Thereafter, we simulate and analyse the propagation of particles in a solar wind containing a corotating interaction region (CIR). We study the particle intensities and anisotropies measured by a fleet of virtual observers located at different positions in the heliosphere, as well as the global distribution of particles in interplanetary space. Results. The differential intensity-time profiles obtained in the simulations using the nominal Parker solar wind solutions illustrate the considerable adiabatic deceleration undergone by SEPs, especially when propagating in a fast solar wind. In the case of the solar wind containing a CIR, we observe that particles adiabatically accelerate when propagating in the compression waves bounding the CIR at small radial distances. In addition, for r ≳ 1.5 AU, there are particles accelerated by the reverse shock as indicated by, for example, the anisotropies and pitch-angle distributions of the particles. Moreover, a decrease in high-energy particles at the stream interface (SI) inside the CIR is observed. The compression/shock waves and the magnetic configuration near the SI may also act as a magnetic mirror, producing long-lasting high intensities at small radial distances. We also illustrate how the efficiency of the cross-field diffusion in spreading particles in the heliosphere is enhanced due to compressed magnetic fields. Finally, the inclusion of cross-field diffusion enables some particles to cross both the forward compression wave at small radial distances and the forward shock at larger radial distances. This results in the formation of an accelerated particle population centred on the forward shock, despite the lack of magnetic connection between the particle injection region and this shock wave. Particles injected in the fast solar wind stream cannot reach the forward shock since the SI acts as a diffusion barrier.


2013 ◽  
Vol 65 (3) ◽  
pp. 63 ◽  
Author(s):  
Kumi Ishikawa ◽  
Yuichiro Ezoe ◽  
Yoshizumi Miyoshi ◽  
Naoki Terada ◽  
Kazuhisa Mitsuda ◽  
...  

2020 ◽  
Author(s):  
Mikhail Fridman

<p>So far, the problem of a short-term forecast of geomagnetic storms can be considered as solved. Meanwhile, mid-term prognoses of geomagnetic storms with an advance time from 3 hours to 3 days are still unsuccessful (see  https://www.swpc.noaa.gov/sites/default/files/images/u30/Max%20Kp%20and%20GPRA.pdf).</p><p> This fact suggests a necessity of looking for specific processes in the solar wind preceding geomagnetic storms. Knowing that magnetic cavities filled with magnetic islands and current sheets are formed in front of high-speed streams of any type (Khabarova et al., 2015, 2016, 2018; Adhikari et al., 2019), we have performed an analysis of the corresponding ULF variations in the solar wind density observed at the Earth's orbit from hours to days before the arrival of a geoeffective stream or flow. The fact of the occurrence of ULF-precursors of geomagnetic storms was noticed a long time ago (Khabarova 2007; Khabarova & Yermolaev, 2007) and related prognostic methods were recently developed (Kogai et al. 2019), while the problem of automatization of the prognosis remained unsolved.</p><p> A new geomagnetic storm forecast method, which employs a Recurrent Neural Network (RNN) for an automatic pattern search, is proposed. An ability of self-teaching and extracting deeply hidden non-linear patterns is the main advantage of Deep Neural Networks (DNNs) with multiple layers over traditional Machine Learning methods. We show a success of the RNN method, using either the unprocessed solar wind density data or Wavelet analysis coefficients as the input parameter for a DNN to perform an automatic mid-term prognosis of geomagnetic storms.  </p><p>Adhikari, L., et al. 2019, The Role of Magnetic Reconnection–associated Processes in Local Particle Acceleration in the Solar Wind, ApJ, 873, 1, 72, https://doi.org/10.3847/1538-4357/ab05c6<br>Kogai T.G. et al., Pre-storm ULF variations in the solar wind density and interplanetary magnetic field as key parameters to build a mid-term prognosis of geomagnetic storms. “GRINGAUZ 100: PLASMA IN THE SOLAR SYSTEM”, IKI RAS, Moscow, June 13–15, 2018, 140-143, ISBN 978-5-00015-043-6. https://www.researchgate.net/publication/327781146_Pre-storm_ULF_variations_in_the_solar_wind_density_and_interplanetary_magnetic_field_as_key_parameters_to_build_a_mid-term_prognosis_of_geomagnetic_storms<br> Khabarova O. V., et al. 2018,  Re-acceleration of energetic particles in large-scale heliospheric magnetic cavities, Proceedings of the IAU, 76-82, https://doi.org/10.1017/S1743921318000285 <br>Khabarova O.V., et al. Small-scale magnetic islands in the solar wind and their role in particle acceleration. II. Particle energization inside magnetically confined cavities. 2016, ApJ, 827, 122, http://iopscience.iop.org/article/10.3847/0004-637X/827/2/122<br>Khabarova O., et al. Small-scale magnetic islands in the solar wind and their role in particle acceleration. 1. Dynamics of magnetic islands near the heliospheric current sheet. 2015, ApJ, 808, 181, https://doi.org/10.1088/0004-637X/808/2/181</p><p>Khabarova O.V., Current Problems of Magnetic Storm Prediction and Possible Ways of Their Solving. Sun&Geosphere,  http://sg.shao.az/v2n1/SG_v2_No1_2007-pp-33-38.pdf , 2(1), 33-38, 2007</p><p>Khabarova O.V. & Yu.I.Yermolaev, Solar wind parameters' behavior before and after magnetic storms, JASTP, 70, 2-4, 2008, 384-390, http://dx.doi.org/10.1016/j.jastp.2007.08.024</p>


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