scholarly journals A correlation study regarding the AE index and ACE solar wind data for Alfvénic intervals using wavelet decomposition and reconstruction

2017 ◽  
Author(s):  
Fernando L. Guarnieri ◽  
Bruce T. Tsurutani ◽  
Luis E. A. Vieira ◽  
Rajkumar Hajra ◽  
Ezequiel Echer ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Wavelet Decomposition ◽  
Correlation Study ◽  
Reconstruction Technique ◽  
Relativistic Electrons ◽  
Ae Index ◽  
Solar Wind Magnetic Field ◽  
Cross Correlation Analysis ◽  
Main Input

Abstract. The purpose of this study is to present a wavelet interactive filtering and reconstruction technique and apply this to the solar wind magnetic field components detected at the L1 Lagrange point ~ 0.01 AU upstream of the Earth. This filtered interplanetary magnetic field (IMF) data is fed into a model to calculate a time series which we call AE*. This model was adjusted assuming that magnetic reconnection associated with southward directed IMF Bz is the main mechanism transferring energy into the magnetosphere. The calculated AE* was compared to the observed AE index using cross correlation analysis. The results show correlations as high as 0.90. Empirical removal of the high-frequency, short-wavelength Alfvénic component in the IMF by wavelet decomposition is shown to dramatically improve the correlation between AE* and the observed AE index. It is envisioned that this AE* can be used as the main input for a model to forecast relativistic electrons in the Earth's outer radiation belts, which are delayed by ~ 1 to 2 days from intense AE events.

scholarly journals A correlation study regarding the AE index and ACE solar wind data for Alfvénic intervals using wavelet decomposition and reconstruction

2018 ◽  
Vol 25 (1) ◽  
pp. 67-76 ◽  
Author(s):  
Fernando L. Guarnieri ◽  
Bruce T. Tsurutani ◽  
Luis E. A. Vieira ◽  
Rajkumar Hajra ◽  
Ezequiel Echer ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Wavelet Decomposition ◽  
Correlation Study ◽  
Reconstruction Technique ◽  
Relativistic Electrons ◽  
Ae Index ◽  
Solar Wind Magnetic Field ◽  
Cross Correlation Analysis ◽  
Main Input

Abstract. The purpose of this study is to present a wavelet interactive filtering and reconstruction technique and apply this to the solar wind magnetic field components detected at the L1 Lagrange point  ∼  0.01 AU upstream of the Earth. These filtered interplanetary magnetic field (IMF) data are fed into a model to calculate a time series which we call AE∗. This model was adjusted assuming that magnetic reconnection associated with southward-directed IMF Bz is the main mechanism transferring energy into the magnetosphere. The calculated AE∗ was compared to the observed AE (auroral electrojet) index using cross-correlation analysis. The results show correlations as high as 0.90. Empirical removal of the high-frequency, short-wavelength Alfvénic component in the IMF by wavelet decomposition is shown to dramatically improve the correlation between AE∗ and the observed AE index. It is envisioned that this AE∗ can be used as the main input for a model to forecast relativistic electrons in the Earth's outer radiation belts, which are delayed by  ∼  1 to 2 days from intense AE events.

Tsallis Distribution Functions in the Solar Wind: Magnetic Field and Velocity Observations

2007 ◽  
Author(s):  
Leonard F. Burlaga ◽  
Adolfo F. Viñas ◽  
Sumiyoshi Abe ◽  
Hans Herrmann ◽  
Piero Quarati ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Distribution Functions ◽  
Solar Wind Magnetic Field ◽  
Tsallis Distribution

scholarly journals Finite size scaling in the solar wind magnetic field energy density as seen by WIND

2002 ◽  
Vol 29 (10) ◽  
pp. 86-1-86-4 ◽  
Author(s):  
B. Hnat ◽  
S. C. Chapman ◽  
G. Rowlands ◽  
N. W. Watkins ◽  
W. M. Farrell
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Energy Density ◽  
Finite Size ◽  
Field Energy ◽  
Finite Size Scaling ◽  
Size Scaling ◽  
Magnetic Field Energy ◽  
Solar Wind Magnetic Field ◽  
Field Energy Density

scholarly journals Predictions of local ground geomagnetic field fluctuations during the 7-10 November 2004 events studied with solar wind driven models

2005 ◽  
Vol 23 (9) ◽  
pp. 3095-3101 ◽  
Author(s):  
P. Wintoft ◽  
M. Wik ◽  
H. Lundstedt ◽  
L. Eliasson
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Flow Direction ◽  
Strong Dependence ◽  
Solar Wind Plasma ◽  
Magnetic Field Data ◽  
Solar Wind Magnetic Field ◽  
Solar Wind Flow ◽  
Field Fluctuations ◽  
Ground Magnetic

Abstract. The 7-10 November 2004 period contains two events for which the local ground magnetic field was severely disturbed and simultaneously, the solar wind displayed several shocks and negative Bz periods. Using empirical models the 10-min RMS and at Brorfelde (BFE, 11.67° E, 55.63° N), Denmark, are predicted. The models are recurrent neural networks with 10-min solar wind plasma and magnetic field data as inputs. The predictions show a good agreement during 7 November, up until around noon on 8 November, after which the predictions become significantly poorer. The correlations between observed and predicted log RMS is 0.77 during 7-8 November but drops to 0.38 during 9-10 November. For RMS the correlations for the two periods are 0.71 and 0.41, respectively. Studying the solar wind data for other L1-spacecraft (WIND and SOHO) it seems that the ACE data have a better agreement to the near-Earth solar wind during the first two days as compared to the last two days. Thus, the accuracy of the predictions depends on the location of the spacecraft and the solar wind flow direction. Another finding, for the events studied here, is that the and models showed a very different dependence on Bz. The model is almost independent of the solar wind magnetic field Bz, except at times when Bz is exceptionally large or when the overall activity is low. On the contrary, the model shows a strong dependence on Bz at all times.

scholarly journals The low-frequency break observed in the slow solar wind magnetic spectra

2019 ◽  
Vol 627 ◽  
pp. A96 ◽  
Author(s):  
R. Bruno ◽  
D. Telloni ◽  
L. Sorriso-Valvo ◽  
R. Marino ◽  
R. De Marco ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Low Frequency ◽  
Slow Solar Wind ◽  
Velocity Spectrum ◽  
Plasma Parameters ◽  
Solar Wind Magnetic Field ◽  
Fast Wind ◽  
Slow Wind ◽  
First Time

Fluctuations of solar wind magnetic field and plasma parameters exhibit a typical turbulence power spectrum with a spectral index ranging between ∼5/3 and ∼3/2. In particular, at 1 AU, the magnetic field spectrum, observed within fast corotating streams, also shows a clear steepening for frequencies higher than the typical proton scales, of the order of ∼3 × 10−1 Hz, and a flattening towards 1/f at frequencies lower than ∼10−3 Hz. However, the current literature reports observations of the low-frequency break only for fast streams. Slow streams, as observed to date, have not shown a clear break, and this has commonly been attributed to slow wind intervals not being long enough. Actually, because of the longer transit time from the Sun, slow wind turbulence would be older and the frequency break would be shifted to lower frequencies with respect to fast wind. Based on this hypothesis, we performed a careful search for long-lasting slow wind intervals throughout 12 years of Wind satellite measurements. Our search, based on stringent requirements not only on wind speed but also on the level of magnetic compressibility and Alfvénicity of the turbulent fluctuations, yielded 48 slow wind streams lasting longer than 7 days. This result allowed us to extend our study to frequencies sufficiently low and, for the first time in the literature, we are able to show that the 1/f magnetic spectral scaling is also present in the slow solar wind, provided the interval is long enough. However, this is not the case for the slow wind velocity spectrum, which keeps the typical Kolmogorov scaling throughout the analysed frequency range. After ruling out the possible role of compressibility and Alfvénicity for the 1/f scaling, a possible explanation in terms of magnetic amplitude saturation, as recently proposed in the literature, is suggested.

Solar Wind Magnetic Field Bending of Jovian Dust Trajectories

Science ◽  
1996 ◽  
Vol 274 (5292) ◽  
pp. 1501-1503 ◽  
Author(s):  
H. A. Zook ◽  
E. Grun ◽  
M. Baguhl ◽  
D. P. Hamilton ◽  
G. Linkert ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Solar Wind Magnetic Field

scholarly journals Anisotropy of the Taylor scale and the correlation scale in plasma sheet and solar wind magnetic field fluctuations

2009 ◽  
Vol 114 (A7) ◽  
pp. n/a-n/a ◽  
Author(s):  
James M. Weygand ◽  
W. H. Matthaeus ◽  
S. Dasso ◽  
M. G. Kivelson ◽  
L. M. Kistler ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Plasma Sheet ◽  
Solar Wind Magnetic Field ◽  
Field Fluctuations ◽  
Correlation Scale
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