scholarly journals Continuous wavelet transform based time-scale and multifractal analysis of the nonlinear oscillations in a hollow cathode glow discharge plasma

2009 ◽  
Vol 16 (10) ◽  
pp. 102307 ◽  
Author(s):  
Md. Nurujjaman ◽  
Ramesh Narayanan ◽  
A. N. Sekar Iyengar
Keyword(s):  
Wavelet Transform ◽  
Glow Discharge ◽  
Hollow Cathode ◽  
Continuous Wavelet Transform ◽  
Time Scale ◽  
Multifractal Analysis ◽  
Discharge Plasma ◽  
Nonlinear Oscillations ◽  
Glow Discharge Plasma ◽  
Continuous Wavelet

Continuous wavelet transform analysis for self-similarity properties of turbulence in magnetized DC glow discharge plasma

2013 ◽  
Vol 79 (5) ◽  
pp. 885-891 ◽  
Author(s):  
BORNALI SARMA ◽  
SOURABH S. CHAUHAN ◽  
A. M. WHARTON ◽  
A. N. SEKAR IYENGAR
Keyword(s):  
Experimental Data ◽  
Wavelet Transform ◽  
Glow Discharge ◽  
Continuous Wavelet Transform ◽  
Discharge Plasma ◽  
Magnetized Plasma ◽  
Glow Discharge Plasma ◽  
Continuous Wavelet ◽  
Dc Glow Discharge ◽  
Self Similarity

AbstractCharacterization of self-similarity properties of turbulence in magnetized plasma is being carried out in DC glow discharge plasma. The time series floating potential fluctuation experimental data are acquired from the plasma by Langmuir probe. Continuous wavelet transform (CWT) analysis considering db4 mother wavelet has been applied to the experimental data and self-similarity properties are detected by evaluating the Hurst exponent from the wavelet variance plotting. From the CWT spectrum, effort is made to extract a highly correlated frequency by locating the brightest spot. Accordingly, those signals are treated for finding out correlation dimension and the Liapunov exponent so that the exact frequency responsible for the chaotic behavior could be found out.

scholarly journals Optogalvanic effects in a hollow cathode glow discharge plasma

1984 ◽  
Vol 56 (7) ◽  
pp. 2047-2055 ◽  
Author(s):  
E. M. van Veldhuizen ◽  
F. J. de Hoog ◽  
D. C. Schram
Keyword(s):  
Glow Discharge ◽  
Hollow Cathode ◽  
Discharge Plasma ◽  
Glow Discharge Plasma

Spectral decomposition of seismic data with continuous-wavelet transform

Geophysics ◽  
2005 ◽  
Vol 70 (6) ◽  
pp. P19-P25 ◽  
Author(s):  
Satish Sinha ◽  
Partha S. Routh ◽  
Phil D. Anno ◽  
John P. Castagna
Keyword(s):  
Fourier Transform ◽  
Wavelet Transform ◽  
Continuous Wavelet Transform ◽  
Time Scale ◽  
Fixed Time ◽  
Frequency Resolution ◽  
Continuous Wavelet ◽  
Window Length ◽  
Time Frequency ◽  
Frequency Map

This paper presents a new methodology for computing a time-frequency map for nonstationary signals using the continuous-wavelet transform (CWT). The conventional method of producing a time-frequency map using the short time Fourier transform (STFT) limits time-frequency resolution by a predefined window length. In contrast, the CWT method does not require preselecting a window length and does not have a fixed time-frequency resolution over the time-frequency space. CWT uses dilation and translation of a wavelet to produce a time-scale map. A single scale encompasses a frequency band and is inversely proportional to the time support of the dilated wavelet. Previous workers have converted a time-scale map into a time-frequency map by taking the center frequencies of each scale. We transform the time-scale map by taking the Fourier transform of the inverse CWT to produce a time-frequency map. Thus, a time-scale map is converted into a time-frequency map in which the amplitudes of individual frequencies rather than frequency bands are represented. We refer to such a map as the time-frequency CWT (TFCWT). We validate our approach with a nonstationary synthetic example and compare the results with the STFT and a typical CWT spectrum. Two field examples illustrate that the TFCWT potentially can be used to detect frequency shadows caused by hydrocarbons and to identify subtle stratigraphic features for reservoir characterization.

Sign in / Sign up

Export Citation Format

Share Document