Statistical Analysis of Langmuir Waves Associated with Type III Radio Bursts: I. Wind Observations

2011 ◽  
Vol 20 (4) ◽  
Author(s):  
S. Vidojević ◽  
A. Zaslavsky ◽  
M. Maksimović ◽  
M. Dražić ◽  
O. Atanacković
Keyword(s):  
Plasma Frequency ◽  
Probability Distributions ◽  
Langmuir Waves ◽  
Type Iii ◽  
Power Spectral ◽  
Spectrum Density ◽  
Wind Spacecraft ◽  
Log Normal ◽  
The Waves ◽  
Log Normal Distribution

AbstractInterplanetary electron beams are unstable in the solar wind and they generate Langmuir waves at the local plasma frequency or its harmonic. Radio observations of the waves in the range 4-256 kHz, observed in 1994-2010 with the WAVES experiment onboard the WIND spacecraft, are statistically analyzed. A subset of 36 events with Langmuir waves and type III bursts occurring at the same time was selected. After removal of the background, the remaining power spectral density is modeled by the Pearson system of probability distributions (types I, IV and VI). The Stochastic Growth Theory (SGT) predicts log-normal distribution for the power spectrum density of the Langmuir waves. Our results indicate that SGT possibly requires further verification.

scholarly journals Statistical behavior of foreshock Langmuir waves observed by the Cluster wideband data plasma wave receiver

2004 ◽  
Vol 22 (7) ◽  
pp. 2337-2344 ◽  
Author(s):  
K. Sigsbee ◽  
C. A. Kletzing ◽  
D. A. Gurnett ◽  
J. S. Pickett ◽  
A. Balogh ◽  
...  
Keyword(s):  
Electric Field ◽  
Plasma Wave ◽  
Probability Distributions ◽  
Langmuir Wave ◽  
Growth Theory ◽  
Langmuir Waves ◽  
Electric Field Amplitude ◽  
Statistical Behavior ◽  
Log Normal ◽  
The Waves

Abstract. We present the statistics of Langmuir wave amplitudes in the Earth's foreshock using Cluster Wideband Data (WBD) Plasma Wave Receiver electric field waveforms from spacecraft 2, 3 and 4 on 26 March 2002. The largest amplitude Langmuir waves were observed by Cluster near the boundary between the foreshock and solar wind, in agreement with earlier studies. The characteristics of the waves were similar for all three spacecraft, suggesting that variations in foreshock structure must occur on scales greater than the 50-100km spacecraft separations. The electric field amplitude probability distributions constructed using waveforms from the Cluster WBD Plasma Wave Receiver generally followed the log-normal statistics predicted by stochastic growth theory for the event studied. Comparison with WBD receiver data from 17 February 2002, when spacecraft 4 was set in a special manual gain mode, suggests non-optimal auto-ranging of the instrument may have had some influence on the statistics.

The statistics of waves propagating in a one-dimensional random medium

1985 ◽  
Vol 398 (1815) ◽  
pp. 341-363 ◽  
Keyword(s):  
Brownian Motion ◽  
Decay Rate ◽  
Normal Distribution ◽  
Random Medium ◽  
Transmitted Intensity ◽  
One Dimensional ◽  
Time Harmonic ◽  
Log Normal ◽  
The Waves ◽  
Log Normal Distribution

We consider the one-dimensional scattering of waves in a time-independent random medium. The waves considered are time-harmonic. It is assumed that the wavelength of the waves and the correlation length of the scatterers are small compared with the distance required for significant scattering. Stochastic process theory is used to investigate the statistics of the wavefield. The problem of a wave incident on a length of random medium is investigated in two cases. The first is where the medium is backed by a perfectly reflecting boundary. Here the intensity is shown to be a product of two factors; an exponential term that decays into the medium and the exponential of a ‘Brownian motion’ that describes the fluctuations of intensity with different realizations of the random medium. Because a Brownian motion has a normal distribution, the intensity has a log–normal distribution at any fixed point in the interior of the medium. For a typical realization of the random medium the exponential decay leads to most of the wave energy being near the front of a long medium. However, it is shown that the average intensity is independent of position in the medium. This is because of the long tail of the log–normal distribution and comes about because the average is heavily weighted by exceptional realizations of the medium. Thus the average value of the intensity, unlike the average of the logarithm of the intensity, is not representative of the intensity in a typical realization. The exponential decay of intensity is a result of the phenomenon of Anderson localization, which has received much attention in solid-state physics. The second case considered is where there is no barrier at the back of the medium. For large lengths of the random medium, it is shown that the transmitted intensity has an approximately log–normal distribution. The typical transmitted intensity is exponentially small as a result of localization, the decay rate with length being the same as the decay rate for the previous case. The average transmitted intensity is also exponentially small, but with a different decay rate because of weighting by exceptional realizations. The third problem discussed is that of the response of a random medium to time-harmonic forcing in the interior. The boundaries are taken to be perfectly reflecting and the response is found to be localized near the source for a typical realization. This result is related to the existence of localized normal modes in a long medium.

Langmuir Waves and Type III Bursts Observed by the Wind Spacecraft

2010 ◽  
Author(s):  
Sonja Vidojević ◽  
Arnaud Zaslavsky ◽  
Milan Maksimovic ◽  
Olga Atanacković ◽  
Sang Hoang ◽  
...  
Keyword(s):  
Langmuir Waves ◽  
Type Iii ◽  
Wind Spacecraft

scholarly journals Improvement of Road Safety through Appropriate Cargo Securing Using Outliers

2021 ◽  
Vol 13 (5) ◽  
pp. 2688
Author(s):  
Martin Vlkovský ◽  
Jiří Neubauer ◽  
Jiří Malíšek ◽  
Jaroslav Michálek
Keyword(s):  
Normal Distribution ◽  
Road Safety ◽  
Statistical Evaluation ◽  
Probability Distributions ◽  
Statistical Comparison ◽  
Vehicle Accidents ◽  
Transport Experiment ◽  
Log Normal ◽  
The Individual ◽  
Log Normal Distribution

The article focuses on evaluating a transportation experiment that intends to improve road safety by analyzing transport shocks that significantly affect the system of securing the load, vehicle, driver, and other aspects. Within Europe, improper or insufficient securing of loads causes up to 25% of all cargo vehicle accidents. Our transport experiment consists of eight rides of a Tatra truck. The measured values of shocks (acceleration coefficients) are statistically evaluated. Three hypotheses are established for these purposes. First, it is proven that the probability distributions of the shocks values differ statistically significantly among individual rides, namely in their shape and median value. Thus further statistical analyses are performed separately for the individual rides, axes, and the accelerometer locations. These analyses prove significant exceedances of the normatively set limits given by the EN 12195-1:2010 standard, which is potentially risky. Especially for the z axis and y axis, the set 20% limit was exceeded in 75.0% and 56.3% of cases, respectively. In the case of the x axis, the established 20% limit was practically not exceeded at all. The analysis of exceeding the permitted limits (the statistical evaluation of the second and third established hypothesis) is based on boxplots that graphically describe the individual rides, as well as on the found contaminated log-normal distribution of the values of the acceleration coefficients in the individual rides. The last hypothesis regarding exceeding the double value of the permitted limit is rejected. Methods of statistical comparison are used during data analysis. The probability distribution of acceleration coefficients is modeled using a contaminated log-normal distribution.

scholarly journals Distribution of Earthquake Magnitude Levels in Bangladesh

2019 ◽  
Vol 11 (3) ◽  
pp. 15
Author(s):  
Md. Habibur Rahman ◽  
Md. Moyazzem Hossain
Keyword(s):  
Probability Distribution ◽  
Normal Distribution ◽  
Goodness Of Fit ◽  
Probability Distributions ◽  
Earthquake Magnitude ◽  
Human Beings ◽  
Richter Scale ◽  
Log Normal ◽  
Log Normal Distribution ◽  
Best Fit

Earthquakes are one of the main natural hazards which seriously make threats the life and property of human beings. Different probability distributions of the earthquake magnitude levels in Bangladesh are fitted. In terms of graphical assessment and goodness-of-fit criterion, the log-normal distribution is found to be the best fit probability distributions for the earthquake magnitude levels in Bangladesh among the probability distribution considered in this study. The average earthquake magnitude level found 4.67 (in Richter scale) for log-normal distribution and the approximately forty-six percent chance is predicted to take place earthquake magnitude in the interval four to five.

Statistical Analysis of Langmuir Waves Associated with Type III Radio Bursts: II. Simulation and Interpretation of the Wave Energy Distributions

2011 ◽  
Vol 20 (4) ◽  
Author(s):  
M. Maksimović ◽  
S. Vidojević ◽  
A. Zaslavsky
Keyword(s):  
Wave Energy ◽  
Probability Distributions ◽  
Wave Packets ◽  
Low Frequency ◽  
Langmuir Wave ◽  
Type I ◽  
Energy Distributions ◽  
Langmuir Waves ◽  
Pearson Type ◽  
Log Normal

AbstractWe have modeled electrostatic Langmuir waves by an electric field, consisting of superposition of Gaussian wave packets with several probability distributions of amplitudes and with several Poisson distributions of wave packets. The outcome of the model is that the WIND satellite observations, especially in the low frequency domain (the WAVES experiment), do not allow to conclude whether the input wave amplitude distributions are closer to the log-normal than to the Pearson type I or uniform. The average number of wave packets in 1 s is found to be between 0.1 and 50. Therefore, there is a clear need to measure Langmuir wave energy distributions directly at the waveform level, not a posteriori in the spectral domain. This is planned to be implemented on the RPW (Radio and Plasma Wave Analyzer) instrument in the Solar Orbiter mission.

scholarly journals The Mechanism Responsible for 'Shadow' Type III Solar Radio Bursts. II. Absorption due to Ion Sound Turbulence

1974 ◽  
Vol 27 (2) ◽  
pp. 271 ◽  
Author(s):  
DB Melrose
Keyword(s):  
Energy Density ◽  
Solar Radio ◽  
Plasma Frequency ◽  
Radio Bursts ◽  
Sound Waves ◽  
Solar Radio Bursts ◽  
Langmuir Waves ◽  
Transverse Waves ◽  
Type Iii ◽  
Ion Plasma

The hypothesis is explored that ion sound turbulence generated by the exciting agency for type III bursts is responsible for shadow type III events. The possible absorption mechanisms are listed: the most favourable are the coalescence of transverse waves and ion sound waves into Langmuir waves or the decay of transverse waves into Langmuir waves and ion sound waves. These mechanisms can operate only if the background source emits at the fundamental plasma frequency and the absorbing region is directly above it (;$ 3 x 104 km). It is found that the event discussed by Kai (1973) can be explained in terms of such absorption with reasonable parameters, e.g. with an energy density in ion sound turbulence W' ~ 10-12 ergcm- 3 at frequencies co' ~ O�3cop! (where cop! is the ion plasma frequency).

scholarly journals A Universal Model for the Log-Normal Distribution of Elasticity in Polymeric Gels and Its Relevance to Mechanical Signature of Biological Tissues

Biology ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 64
Author(s):  
Arnaud Millet
Keyword(s):  
Elastic Modulus ◽  
Normal Distribution ◽  
Biological Tissues ◽  
Force Microscopy ◽  
Polymeric Gels ◽  
Atomic Force ◽  
Clear Explanation ◽  
Log Normal ◽  
Log Normal Distribution

The mechanosensitivity of cells has recently been identified as a process that could greatly influence a cell’s fate. To understand the interaction between cells and their surrounding extracellular matrix, the characterization of the mechanical properties of natural polymeric gels is needed. Atomic force microscopy (AFM) is one of the leading tools used to characterize mechanically biological tissues. It appears that the elasticity (elastic modulus) values obtained by AFM presents a log-normal distribution. Despite its ubiquity, the log-normal distribution concerning the elastic modulus of biological tissues does not have a clear explanation. In this paper, we propose a physical mechanism based on the weak universality of critical exponents in the percolation process leading to gelation. Following this, we discuss the relevance of this model for mechanical signatures of biological tissues.

scholarly journals Extreme geomagnetic activities: a statistical study

2020 ◽  
Vol 72 (1) ◽  
Author(s):  
Ryuho Kataoka
Keyword(s):  
Magnetic Storms ◽  
Magnetic Observatory ◽  
Statistical Distributions ◽  
Limited Data ◽  
Data Set ◽  
Sudden Commencements ◽  
The One ◽  
Log Normal ◽  
Geomagnetic Activities ◽  
Log Normal Distribution

Abstract Statistical distributions are investigated for magnetic storms, sudden commencements (SCs), and substorms to identify the possible amplitude of the one in 100-year and 1000-year events from a limited data set of less than 100 years. The lists of magnetic storms and SCs are provided from Kakioka Magnetic Observatory, while the lists of substorms are obtained from SuperMAG. It is found that majorities of events essentially follow the log-normal distribution, as expected from the random output from a complex system. However, it is uncertain that large-amplitude events follow the same log-normal distributions, and rather follow the power-law distributions. Based on the statistical distributions, the probable amplitudes of the 100-year (1000-year) events can be estimated for magnetic storms, SCs, and substorms as approximately 750 nT (1100 nT), 230 nT (450 nT), and 5000 nT (6200 nT), respectively. The possible origin to cause the statistical distributions is also discussed, consulting the other space weather phenomena such as solar flares, coronal mass ejections, and solar energetic particles.

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