Solar Soft X-Rays Data P eriodic Analysis
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Solar Soft X-Rays Data P Solar Soft X-Rays Data P eriodic eriodic Analysi Analysi Pu Wang Pu Wang Department of Astronomy Department of Astronomy , Nanjing University , Nanjing University July 9, 2005 July 9, 2005 [email protected] [email protected] The First Chinese-Korean Solar Physics The First Chinese-Korean Solar Physics Workshop Workshop
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The First Chinese-Korean Solar Physics Workshop. Solar Soft X-Rays Data P eriodic Analysis. Pu Wang Department of Astronomy , Nanjing University July 9, 2005 [email protected]. Outline of Presentation. 1. Introduction. 2. Data and Analysis Methods. 3. Periodicity Analysis Results. - PowerPoint PPT Presentation
Transcript of Solar Soft X-Rays Data P eriodic Analysis
Solar Soft X-Rays Data PSolar Soft X-Rays Data Periodiceriodic AnalysisAnalysis
Pu WangPu WangDepartment of AstronomyDepartment of Astronomy , Nanjing University, Nanjing University
July 9, 2005July 9, [email protected]@nju.edu.cn
The First Chinese-Korean Solar Physics WorkshopThe First Chinese-Korean Solar Physics Workshop
Outline of Presentation
1. Introduction
5. Future Works
2. Data and Analysis Methods
3. Periodicity Analysis Results
4. Discussion and Summary
1. Introduction
As a long-term periodicity, the Sun exhibits the 11-year sunspot cycle, which ha
s been known for a long time. For short terms, the Sun often exhibits 27-d and 1
3.5-d periodicities, which tell more about spatial organization of the solar activity
than its temporal organization. The regime between these extremes of time scal
es (between 27 d and 11 y) is called the “mid range.”
Periodicities in this mid range have been explored, starting with the discovery of
a 153-d periodicity in -ray flare occurrence (Rieger et al. 1984). Since then, man
y researchers investigated mid-range periodicities, using various solar activity in
dicators.
Many researchers studied periodicities in sunspot areas and numbers.
Analysis of flare data of different solar cycles found other periodicities.
1. Introduction
51-d period in flares selected by CFI (comprehensive flare index) during cycle 19
(Bai 1987)
The 77 day periodicity in the flare rate of cycle 22 (Astrophysical Journal)
78-d period in flares selected by microwave-peak flux during cycle 20 (Bogart &
Bai 1985)
84-d period in CFI-selected flares during cycle 20 (Bai 1992b)
127-d period in flares selected by CFI and flares selected by 10-cm radio peak fl
ux
The ~150 day quasi-periodicity in interplanetary and solar phenomena during cyc
le 23
Evidence for a fundamental period of the sun and its relation to the 154 day com
plex of periodicities
On the 24- and 155-day periodicity observed in solar Hα flares
1. Introduction
It is important to detect mid-range flare periodicities and to calculate accurately
their statistical significances because flare periodicities can provide information
on properties of the Sun.
Flare periodicities can provide information on properties of the Sun.
Using X-ray flux to analyze the Flare periodicities can provide accurate
information on properties of the Sun.
Flare periodicities in earlier cycles (19–22) have been studied by many authors,
but it seems necessary reanalyze them with the different methods so that we
can compare statistical significances of several periodicities analyzed
previously with different methods.
2. Data and Analysis Methods
GOES SPACE ENVIRONMENT MONITOR 1-Minute & 5-
Minute Averages Data
1986.01.01-2005.05.31
XL 1 - 8 Å X-rays (Watts/m2)
XS 0.5 - 3 Å X-rays, or 0.5 – 4 Å prior to GOES-8 (Watts/m2)
The GOES X-ray Sensor (XRS) data have recently been used
in new ways for forecasting and specifying conditions.
The Wavelet Transform
txx dt
s
ttx
sssCWT
1),(),(
Continuous wavelet transform of the signal x(t) using the analysis wavelet (.)
Translation parameter, measure of time
Scale parameter, measure of frequency
The mother wavelet. All kernels are obtained by translating (shifting) and/or scaling the mother wavelet
A normalization constant Signal to be
analyzed
Scale = 1/frequency
2. Data and Analysis Methods
24-hours integrated soft x-ray flux.
Using Morlet mother wavelet function
This wavelet has no scaling function, but i
s explicit.
2 / 2( ) cos(5 )xx Ce x
1986.01.01-1996.12.31 XL Day
3. Periodicity Analysis Results
Confirmed periodicity: 25.5,77
New periodicity:
230
1986.01.01-1996.12.31 XS day
3. Periodicity Analysis Results
Confirmed periodicity: 25.5,77,127
3. Periodicity Analysis Results
Confirmed periodicity: 25.5,77,152
New periodicity:230
1999.02.05-2003.02.10 XL day
1999.02.05-2003.02.10 XS day
3. Periodicity Analysis Results
Confirmed periodicity: 25.5,77,127
New periodicity:230
3. Periodicity Analysis Results
Confirmed periodicity: 25.5,77,152
New periodicity:
230
1997.01.01-2005.05.31 XL day
1997.01.01-2005.05.31 XS day
3. Periodicity Analysis Results
Confirmed periodicity: 25.5,77,152
1986.01.01-2005.05.31 XL day
3. Periodicity Analysis Results
Confirmed periodicity: 25.5,77
New periodicity:230
1986.01.01-2005.05.31 XS day
3. Periodicity Analysis Results
Confirmed periodicity: 25.5,77,127,152
New periodicity:230
4. Discussion and Summary
• By using soft x-ray flux data, we can also find 25.5, 77, 127,
152-d Periodicities.
• Interesting probably 230-d Periodicity have been found by a
nalyzing soft x-ray flux data.
• Different time scale show different Periodicity .
• Using soft x-ray flux data also can accurately describe the so
lar activity Periodicity
• The results presented may provide useful information for the
space weather forecast
5. Future Works
• The results may provide useful information for the space wea
ther forecast, and the validity needs to be verified by observat
ions.
• The observational examples and statistical results will be dev
oted to our Future works.
• Some solar flare occurrence periodicities should be confirme
d by other ideas.
Thank you!
The First Chinese-Korean Solar Physics The First Chinese-Korean Solar Physics WorkshopWorkshop
Thank you!
The First Chinese-Korean Solar Physics The First Chinese-Korean Solar Physics WorkshopWorkshop
