Spatially resolved minute periodicities of microwave emission during a strong solar flare
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SPATIALLY RESOLVED MINUTE PERIODICITIES OF MICROWAVE EMISSION DURING A STRONG SOLAR FLARE PowerPoint PPT Presentation


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SPATIALLY RESOLVED MINUTE PERIODICITIES OF MICROWAVE EMISSION DURING A STRONG SOLAR FLARE. Kupriyanova E. 1 ,Melnikov V. 1 , Shibata K. 2,3 , Shibasaki K. 4. 1 Pulkovo Observatory, Russia 2 Kyoto University, Japan 3 Kwasan and Hida Observatory, Japan

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SPATIALLY RESOLVED MINUTE PERIODICITIES OF MICROWAVE EMISSION DURING A STRONG SOLAR FLARE

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Spatially resolved minute periodicities of microwave emission during a strong solar flare

SPATIALLY RESOLVED MINUTE PERIODICITIES OF MICROWAVE EMISSION DURING A STRONG SOLAR FLARE

Kupriyanova E.1,Melnikov V.1, Shibata K.2,3, Shibasaki K.4

1 Pulkovo Observatory, Russia

2 Kyoto University, Japan

3 Kwasan and Hida Observatory, Japan

4 Nobeyama Solar Radio Observatory,Japan


Spatially resolved minute periodicities of microwave emission during a strong solar flare

Introduction

1.

Until recent time, quasi-periodic pulsations (QPPs) with periods from 1 to 15 minutes have been observed in solar microwave emission above the sunspots only (Gelfreikh et al., Solar Phys., V.185, P.177, 1999).

Last time, QPPs with that periods became to appear during the flares also. In the microwaves. They was discribed in the papers:

Zaitsev et al., Cosmic Research, V.46, P.301, 2008;Meszarosova et al., Astron. Astrophys., V.697, P. L108, 2009; Sych et al., Astron. Astrophys., V.505, P.791, 2009;Reznikova, Shibasaki, Astron. Astrophys., V.525, P.A112, 2011; Kim et al., The Astrophysical Journal Letters, V. 756, P. L36, 2012

In X-rays, minute QPPs were studied byJakimiec and Tomczak (Solar Phys., V.261, P.233, 2010)

Studies of these oscillations became especially topicalin view oftheir possiblerelationship to flare energyrelease and heating ofthe solar corona:

Nakariakov and Zimovets, Astrophys. J.L., V.730. P.L27, 2011;

Zaitsev and Kislyakova, Radiophys. Quant. El., V.55. P.429. 2012.

The aim

2.

Study of the spatial structure of QPPs with periods of several minutes in the microwave emission of the solar flare on May 14, 2013.


Spatially resolved minute periodicities of microwave emission during a strong solar flare

Methodology.Analysis of QPPs in Time Profiles

3.

  • 1. Time profiles of high-frequency component are calculated for each box using formula

    (1)

    HereF(t) is original flux (Stokes I or Stokes V) from a whole box, Fsm(t)is its low-frequency background obtained using method of running average with time intervals = 30500 s.

  • 2. The time profiles D(t) are studied using methods of correlation, Fourier and wavelet analysis.

    3. For eacht :

    auto-correletion functions R(D) and their Fourier periodograms;

    wavelet spectra of D.

Analysis of spatial structure of QPPs

  • 4. NoRH radio maps at 17 and 34 GHz are built (time cadenceis 1s);

  • 5. small boxes are selected in a different parts of flaring area;

  • 6. time profiles of the integrated fluxes are calculated for each box;

  • 7. the time profiles are studied using the method discribed in items 1-3.


Spatially resolved minute periodicities of microwave emission during a strong solar flare

4.

Integrated (spatially unresolved) time profiles

Fig. 1


Spatially resolved minute periodicities of microwave emission during a strong solar flare

Cross-correlations of NoRH and NoRP signals

4.

Fig. 2

Fig. 3

  • The time profiles of the NoRH correlation amplitudes are well correlated with NoRP integrated flux Fig. 1. Their cross-correlation function at 17 GHz are shown in Fig. 2 (upper panel), and that for 34 GHz(35 GHz) (downer panel).

  • The total time profiles (without detrending) of the NoRH correlation amplitudes are well correlated at frequences 17 GHz and 34 GHz (Fig. 3) with correlation coefficient r ≈ 1.0.

  • The total time profiles (without detrending) of the NoRP fluxes are well correlated at frequences 17 GHz and 34 GHz (Fig. 3) with correlation coefficient r ≈ 0.8.


Spatially resolved minute periodicities of microwave emission during a strong solar flare

5.

Spectral properties of the integrated signal (correlation amplitudes)

Phase of flare maximum01:06:30 – 01:08:00UT.

QPPs with period 50 s are well pronounced at both frequincies.

The time profile at 34 GHz delays relatively to time profile at 17 GHz by 12 s


Spatially resolved minute periodicities of microwave emission during a strong solar flare

6.

Dynamic of the source of microwave emission

Time profiles of emission fluxes intergrated over the whole area


Spatially resolved minute periodicities of microwave emission during a strong solar flare

6.

Dynamic of the source of microwave emission

Variance map

Data cube is stable

N = 1800

from 01:00:00 to 01:29:59 UT


Spatially resolved minute periodicities of microwave emission during a strong solar flare

7.

Analysis of spatial structure of QPPs

Flare maximum phase

QPPs with P ≈1 min reveal obvious delays between time profilesfrom large loop relatively to time profile of the small loop


Spatially resolved minute periodicities of microwave emission during a strong solar flare

8.

Spectral analysis of QPPs

Spectral power

From violet to orange lines

t = 15, 30, 60, 90, 120, 150,180 s

Periods detected:

50 s, 60 s, 100 s, 150 s

10

Period, s


Spatially resolved minute periodicities of microwave emission during a strong solar flare

9.

Cross-correlation analysis of QPPs

Spectral power

The fluxes from box 1, box 2, and box 3 in the big loop delay with respect to the flux from box 0 in the small loop by Dt≈ 36–40 s

11


Spatially resolved minute periodicities of microwave emission during a strong solar flare

Observed periods

Pobs ≈ 50–180 s

T0 = 5·106―2107 K

PSMAI ≈ 61–120 s

L = 22 Mm

n0 = 5·1010–1011 cm-3

PSMAII ≈ 32–60 s

B0 = 300 G

PSMAIII = 20–40 s

a/L≈ 0.2

PSI does not exist

Sausage mode

Kink mode

Slow magneto-acoustic mode

PKI = 12–17 s

PBI = 11–16 s

PSII does not exist

PKII = 6–9 s

PBII = 6–8 s

PSIII = 3–4 s

Balloning mode

PBIII = 4–6 s

PKIII = 4–9 s

Discussion. MHD-oscillations

10.

Standing MHD modes trapped in magnetic tube.


Spatially resolved minute periodicities of microwave emission during a strong solar flare

Observed periods

Pobs ≈ 50–180 s

T0 = 5·106―2107 K

PSMAI ≈ 173–245 s

L = 40 Mm

n0 = 5·1010–1011 cm-3

PSMAII ≈ 87–122 s

B0 = 100 G

PSMAIII = 58–82 s

a/L≈ 0.2

PSI does not exist

Sausage mode

Kink mode

Slow magneto-acoustic mode

PKI = 65–92 s

PBI = 63–89 s

PSII does not exist

PKII = 34–48 s

PBII = 32–45 s

PSIII = 15–21 s

Balloning mode

PBIII = 22–31 s

PKIII = 24–33 s

Discussion. MHD-oscillations

10.

Standing MHD modes trapped in magnetic tube.


Spatially resolved minute periodicities of microwave emission during a strong solar flare

Periods observed

2 L

P =

nvph

Pobs ≈ 1 min

L — loop length

n — harmonic number

vph —phase velocity

L,N0,B0,T0Ne, Be, Te

L1= 40 Mm

L2 = 22 Mm

10.

Discussion. MHD oscillations. Standing waves?

The periods can be caused by SMA mode of MHD oscillations in a loop

The period of the standing MHD wave is:

Dispersion equation for MHD mode in a simplest magnetic loop:

But...

Period is the samein the both loops


Spatially resolved minute periodicities of microwave emission during a strong solar flare

Observed periods

The small loop:

T0 = 5·106 K

T0 = 2·107 K

Pobs ≈ 1 min

n0 = 5·1010 cm-3

n0 = 5·1010 cm-3

B0 =300 G

B0 =300 G

The fundamental PSMAI ≈ 61 s

Second harmonic PSMAII ≈60 s

Delays

SMA waves

D t ≈ 40 s

DL

vph ≈ 330–510 km/s

T0 = 5·106–107 K

n0 = 5·1010–1011 cm-3

B0 =100–300 G

L = 40 Mm

L = 22 Mm

The big loop:

DL≈ 16000 km

DL = vph· Dt

Induced oscillations

11.

15


Spatially resolved minute periodicities of microwave emission during a strong solar flare

Conclusions

Spatially resolved quasi-periodic pulsations (QPPs) periods P = 50, 60, 100, 155, 180 s are found in microwave emission during solar flare on May 14, 2013. Data of Nobeyama Radioheliograph (NoRH) and Radio Polarimeters (NoRP) at 17 GHz and 34 GHz are used.

The QPPs with the same period of P ≈ 1min originate from two flaring loops having different lengths L during the impulsive phase of the flare.

These QPPs in the big loop delays over the QPPs from the small loop by Dt ≈ 40 s.

The periods QPPs in the small loop correspond to the standing SMA mode. QPPs in the large loop are induced by oscillation of the small loop.


Spatially resolved minute periodicities of microwave emission during a strong solar flare

Thank you

for your attention !


Spatially resolved minute periodicities of microwave emission during a strong solar flare

11.

Slow magnetoacoustic waves

in two-ribbon flares?

But...

The loop in the middle appears after the border loops


Spatially resolved minute periodicities of microwave emission during a strong solar flare

is time: i = 0..N–1,N is number of points in time series

Testing the method

5.

Amount of tests is 500

Model function :

s

s

s


Spatially resolved minute periodicities of microwave emission during a strong solar flare

Testing the method

5.

t = 15 s


Spatially resolved minute periodicities of microwave emission during a strong solar flare

t = 20 s

Testing the method

5.


Spatially resolved minute periodicities of microwave emission during a strong solar flare

t= 25 s

Testing the method

5.


Spatially resolved minute periodicities of microwave emission during a strong solar flare

t= 30 s

Testing the method

5.


Spatially resolved minute periodicities of microwave emission during a strong solar flare

t= 40 s

Testing the method

5.


Spatially resolved minute periodicities of microwave emission during a strong solar flare

Testing the method

5.


Spatially resolved minute periodicities of microwave emission during a strong solar flare

Testing the method

5.

Results for period

>90 %

>96 %

>99 %

>99 %


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