discovery of relativistic positrons in solar flares with microwave imaging and polarimetry
DESCRIPTION
Discovery of Relativistic Positrons in Solar Flares with Microwave Imaging and Polarimetry. Gregory D. Fleishman, Alexander T. Altyntsev, Natalia S. Meshalkina NJIT 05 Nov. 2013. HAPPY BIRTHDAY, DALE!. Dale Gary, Research Highlights I. Instrumentation. Owens Valley Solar Array (OVSA) - PowerPoint PPT PresentationTRANSCRIPT
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Discovery of Relativistic Positrons in Solar Flares with Microwave Imaging
and Polarimetry
Gregory D. Fleishman, Alexander T. Altyntsev, Natalia S. Meshalkina
NJIT05 Nov. 2013
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HAPPY BIRTHDAY, D
ALE!
HAPPY BIRTHDAY, D
ALE!
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Dale Gary, Research HighlightsI. Instrumentation
• Owens Valley Solar Array (OVSA)
• Korean Solar Radio Burst Locator (KSRBL)
• FASR Subsystem Testbed (FST)
• EOVSA Subsystem Testbed (EST)
• Expanded OVSA (EOVSA )
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Dale Gary, Research HighlightsII. Research
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Dale Gary, Research HighlightsII. Research
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Dale Gary, Research HighlightsII. Research
276 Citations
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HAPPY BIRTHDAY, D
ALE!
HAPPY BIRTHDAY, D
ALE!
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$6060 Million NSF Grant Will Upgrade
EOVSA to FASR
BEST WISHES, D
ALE!
BEST WISHES, D
ALE!
NEWARK, Nov 5 2013
$60
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Discovery of Relativistic Positrons in Solar Flares with Microwave Imaging
and Polarimetry
Gregory D. Fleishman, Alexander T. Altyntsev, Natalia S. Meshalkina
NJIT05 Nov. 2013
![Page 10: Discovery of Relativistic Positrons in Solar Flares with Microwave Imaging and Polarimetry](https://reader036.vdocuments.us/reader036/viewer/2022062423/56814889550346895db59e9a/html5/thumbnails/10.jpg)
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Plan of the talk• Where relativistic positrons come from in flares?
• What is the positron contribution to the microwave emission?
• How emission by positrons can be distinguished from that by electrons?
• Can this be done with existing microwave databases?
• Data analysis
• Discussion and conclusions
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Origin of Relativistic Positrons in Flares
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Acceleration of Ions
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Polarimetry – a key to positron detection
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Nobeyama Radioheliograph (NoRH) is well suited for our study:
NoRH produces images of intensity (I = R+L) and polarization (V = R – L) at 17 GHz while of the intensity only at 34 GHz. In addition, Nobeyama Polarimeters (NoRP) (Nakajima 1985) observe total power data (both I and V) at a number of singlefrequencies including 17 and 35 GHz. This set of observationaltools suggests the following strategy of identifying properties of solar bursts with unambiguous positron contribution:
(i) single, spatially coinciding, sources at both 17 and 34 GHz; (ii) the 34 GHz emission must come from an area where the 17
GHz V displays a unipolar distribution (i.e., the polarization of 17 GHz emission has a definite sense throughout the region of 34 GHz emission); and
(iii) the total power V must have opposite signs at 17 and 34 GHz.
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Gan et al (2001).
13 Mar 2000
Yohkoh
Yohkoh
NoRP
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Gan et al (2001).
V, 17 GHz, RCPBz, photosphere
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Gan et al (2001).
X-ray
MW
Spectra
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Polarization
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24 Aug 2002>90 MeV70-150 keV
0.7-2 MeV
V.Kurt. Pr. Com.
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17 May 1999
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15 Jul 2004Kawate et al. 2012
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03 Mar 2000
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02 Sep 2001
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23 Apr 1998
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24 Oct 2003
?
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9 Jul 2012
NO
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• High-frequency microwave imaging spectropolarimetry offers a new way of detecting and studying relativistic positrons from solar flares.
• Analysis of the Nobeyama database augmented by other context data reveals around 10 events-candidates with the relativistic positron signature; a few of them unambiguously show all expected evidence, so the conclusion that the positrons dominated in producing high-frequency microwave emission in those events seems inescapable.
• New generation of the radio imaging instruments observing at many high frequencies, such as JVLA and ALMA, promises that the positron contribution to the GS emission can be routinely observed in many events.
• Being observed at many frequencies the relativistic positron energy spectrum and spatial distribution can be measured in great detail as a function of time.
Summary