scholarly journals ANALISIS KONDISI FLUKS ELEKTRON DI SABUK RADIASI ELEKTRON LUAR BERDASARKAN MEDAN MAGNET ANTARPLANET (BZ) DAN KECEPATAN ANGIN MATAHARI (ANALYSIS OF ELECTRON FLUX CONDITION IN OUTER ELECTRON RADIATION BELT BASED ON INTERPLANETARY MAGNETIC FIELD (BZ) AND SOL

2018 ◽  
Vol 15 (1) ◽  
pp. 39
Author(s):  
Siska Filawati
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Wind Speed ◽  
Radiation Belt ◽  
Solar Wind Velocity ◽  
Electron Flux ◽  
Interplanetary Space ◽  
Solar Wind Speed ◽  
Electron Radiation ◽  
Outer Electron

Interplanetary space is a hazard precursor for solar eruption toward earth. The solar eruptions enhance electron flux that can lead to anomalies, shifts, and permanent damage to spacecraft, e.g. satellites. The data used in this paper are interplanetary space data represented by interplanetary magnetic field (Bz) and solar wind speed, as well as Dst and AE indexes as comparison indicating disturbance has reached Earth’s poles and equator during 2011-2012. The method used is to determine the value of maximum and minimum Bz in the year 2011-2012 which is taken five days before and after. Analysis and calculation of correlation is done to data of Bz-electron flux and solar wind velocity-electron flux. Clarification of disturbence in interplanetary space and outer electron radiation belt is using index data Dst and AE indexes are used to clarify interplanetary space and outer electron radiation belt disturbances. The aim of this study is to determine the characteristics of interplanetary space that can increase the electron flux so that the space weather early warning can be done. It was found that the period of electron flux enhancement after decrease and increase of Bz was 2 to 3 days. The electron flux would enhance when interplanetary space was in its normal condition at solar wind speed 500 km/sec and Bz is -5 nT to +5 nT. Electron flux correlation with solar wind velocity was better than with Bz. ABSTRAKKondisi ruang antarplanet merupakan prekursor bahaya erupsi matahari terhadap bumi. Erupsi matahari dapat menyebabkan peningkatan fluks elektron. Tingginya fluks elektron dapat menyebabkan anomali, pergeseran, dan kerusakan permanen pada wahana antariksa, misal satelit. Data yang digunakan pada makalah ini adalah data ruang antarplanet yang diwakili oleh kondisi medan magnet antarplanet (Bz) dan kecepatan angin matahari yang merupakan prekursor peningkatan fluks elektron serta data indeks Dst dan indeks AE sebagai pembanding bahwa gangguan telah mencapai kutub dan ekuator bumi selama rentang waktu 2011-2012. Metode yang digunakan adalah menentukan nilai Bz maksimum dan minimum dalam tahun 2011-2012 yang selanjutnya dari penanggalan data tersebut diambil data lima hari sebelum dan sesudah. Analisis dan perhitungan korelasi dilakukan terhadap data Bz-fluks elektron dan kecepatan angin matahari-fluks elektron. Klarifikasi gangguan yang terjadi di ruang antarplanet dan sabuk radiasi elektron luar menggunakan data indeks Dst dan indeks AE. Tujuan ditulisnya makalah ini adalah untuk mengetahui karakteristik kondisi ruang antarplanet yang dapat meningkatkan fluks elektron agar peringatan dini cuaca antariksa dapat dilakukan. Hasil yang didapatkan adalah waktu yang dibutuhkan fluks elektron setelah terjadi penurunan dan peningkatan Bz adalah 2 hingga 3 hari, fluks elektron akan meningkat saat kondisi ruang antarplanet normal yaitu pada kecepatan 500 km/detik dan Bz -5 nT hingga +5 nT, korelasi fluks elektron dengan kecepatan angin matahari lebih baik dibanding fluks elektron dengan Bz.

scholarly journals The relativistic electron response in the outer radiation belt during magnetic storms

2002 ◽  
Vol 20 (7) ◽  
pp. 957-965 ◽  
Author(s):  
R. H. A. Iles ◽  
A. N. Fazakerley ◽  
A. D. Johnstone ◽  
N. P. Meredith ◽  
P. Bühler
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Wind Speed ◽  
Interplanetary Magnetic Field ◽  
Relativistic Electron ◽  
Radiation Belt ◽  
Solar Wind Speed ◽  
Recovery Phase ◽  
Magnetic Storms ◽  
Outer Radiation Belt

Abstract. The relativistic electron response in the outer radiation belt during magnetic storms has been studied in relation to solar wind and geomagnetic parameters during the first six months of 1995, a period in which there were a number of recurrent fast solar wind streams. The relativistic electron population was measured by instruments on board the two microsatellites, STRV-1a and STRV-1b, which traversed the radiation belt four times per day from L ~ 1 out to L ~ 7 on highly elliptical, near-equatorial orbits. Variations in the E > 750 keV and E > 1 MeV electrons during the main phase and recovery phase of 17 magnetic storms have been compared with the solar wind speed, interplanetary magnetic field z-component, Bz , the solar wind dynamic pressure and Dst *. Three different types of electron responses are identified, with outcomes that strongly depend on the solar wind speed and interplanetary magnetic field orientation during the magnetic storm recovery phase. Observations also confirm that the L-shell, at which the peak enhancement in the electron count rate occurs has a dependence on Dst *.Key words. Magnetospheric physics (energetic particles, trapped; storms and substorms) – Space plasma physics (charged particle motion and accelerations)

scholarly journals Density and temperature of energetic electrons in the Earth's magnetotail derived from high-latitude GPS observations during the declining phase of the solar cycle

2011 ◽  
Vol 29 (10) ◽  
pp. 1755-1763 ◽  
Author(s):  
M. H. Denton ◽  
T. E. Cayton
Keyword(s):  
Solar Wind ◽  
Temperature Distribution ◽  
Electron Density ◽  
Radiation Belt ◽  
Solar Wind Speed ◽  
Energetic Electron ◽  
Electron Radiation ◽  
Outer Electron ◽  
Energetic Electrons ◽  
Speed Solar Wind

Abstract. Single relativistic-Maxwellian fits are made to high-latitude GPS-satellite observations of energetic electrons for the period January 2006–November 2010; a constellation of 12 GPS space vehicles provides the observations. The derived fit parameters (for energies ~0.1–1.0 MeV), in combination with field-line mapping on the nightside of the magnetosphere, provide a survey of the energetic electron density and temperature distribution in the magnetotail between McIlwain L-values of L=6 and L=22. Analysis reveals the characteristics of the density-temperature distribution of energetic electrons and its variation as a function of solar wind speed and the Kp index. The density-temperature characteristics of the magnetotail energetic electrons are very similar to those found in the outer electron radiation belt as measured at geosynchronous orbit. The energetic electron density in the magnetotail is much greater during increased geomagnetic activity and during fast solar wind. The total electron density in the magnetotail is found to be strongly correlated with solar wind speed and is at least a factor of two greater for high-speed solar wind (VSW=500–1000 km s−1) compared to low-speed solar wind (VSW=100–400 km s−1). These results have important implications for understanding (a) how the solar wind may modulate entry into the magnetosphere during fast and slow solar wind, and (b) if the magnetotail is a source or a sink for the outer electron radiation belt.

scholarly journals The role of aerodynamic drag in dynamics of coronal mass ejections

2008 ◽  
Vol 4 (S257) ◽  
pp. 271-277
Author(s):  
Bojan Vršnak ◽  
Dijana Vrbanec ◽  
Jaša Čalogović ◽  
Tomislav Žic
Keyword(s):  
Solar Wind ◽  
Wind Speed ◽  
Coronal Mass Ejections ◽  
Weather Forecasting ◽  
Aerodynamic Drag ◽  
Interplanetary Space ◽  
Solar Wind Speed ◽  
Standard Form ◽  
The Sun

AbstractDynamics of coronal mass ejections (CMEs) is strongly affected by the interaction of the erupting structure with the ambient magnetoplasma: eruptions that are faster than solar wind transfer the momentum and energy to the wind and generally decelerate, whereas slower ones gain the momentum and accelerate. Such a behavior can be expressed in terms of “aerodynamic” drag. We employ a large sample of CMEs to analyze the relationship between kinematics of CMEs and drag-related parameters, such as ambient solar wind speed and the CME mass. Employing coronagraphic observations it is demonstrated that massive CMEs are less affected by the aerodynamic drag than light ones. On the other hand, in situ measurements are used to inspect the role of the solar wind speed and it is shown that the Sun-Earth transit time is more closely related to the wind speed than to take-off speed of CMEs. These findings are interpreted by analyzing solutions of a simple equation of motion based on the standard form for the drag acceleration. The results show that most of the acceleration/deceleration of CMEs on their way through the interplanetary space takes place close to the Sun, where the ambient plasma density is still high. Implications for the space weather forecasting of CME arrival-times are discussed.

scholarly journals Effect of the solar wind conditions on the ionospheric equivalent current systems

2013 ◽  
Vol 31 (3) ◽  
pp. 489-501 ◽  
Author(s):  
J. J. Zhang ◽  
C. Wang ◽  
B. B. Tang ◽  
H. Li
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Wind Speed ◽  
Current System ◽  
Solar Wind Speed ◽  
Lower Latitude ◽  
Equivalent Current ◽  
Mhd Model ◽  
Current Systems ◽  
The Imf

Abstract. We employ a global magnetohydrodynamics (MHD) model, namely the PPMLR-MHD model, to investigate the effect of the solar wind conditions, such as the interplanetary magnetic field (IMF) clock angle, southward IMF magnitude and solar wind speed, on the average pattern of the ionospheric equivalent current systems (ECS). A new method to derive ECS from the MHD model is proposed and applied, which takes account of the oblique magnetic field line effects. The model results indicate that when the IMF is due northward, the ECS are very weak while the current over polar region is stronger than the lower latitude; when the IMF rotates southward, the two-cell current system dominates, the eastward electrojet on the afternoon sector and the westward electrojet on the dawn sector increase rapidly while the westward electrojet is stronger than the eastward electrojet. Under southward IMF, the intensity of the westward electrojet and eastward electrojet both increase with the increase of the southward IMF magnitude and solar wind speed, and the increase is very sharp for the westward electrojet. Furthermore, we compare the geomagnetic perturbations on the ground represented by the simulated average ECS with the observation-based statistical results under similar solar wind conditions. It is found that the model results generally match with the observations, but the underestimation of the eastward equivalent current on the dusk sector is the main limitation of the present model.

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