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14th Solar-Terrestrial Physics Symposium – SCOSTEP – July 9-13, 2018, York University, Toronto, Canada
Transient and long-term solar activity: Origin and impact on the
Earth’s atmosphere
Jean-Pierre Raulin
Centro de Radioastronomia e Astrofísica Mackenzie - CRAAMEngineering School
Universidade Presbiteriana MackenzieSão Paulo
Brazil
Outline
• Why is it important to study solar flares at high radio frequencies ?
• Key observations at w, mm-, submm- - opened questions
• New Long IR observations and planned Mid-IR experiment
• Transient and long-term solar (and non-solar) activity imprints in the lower
ionosphere – D region – VLF technique
• SEP diagnostic
• Conclusions
14th Solar-Terrestrial Physics Symposium – SCOSTEP – July 9-13, 2018, York University, Toronto, Canada
Flare emission at very high radio frequencies
Particle acceleration is a fundamental problem in astrophysics (cosmic rays,
active sun, Earth’s magnetosphere and atmosphere, etc ….)
High-frequency (mm, sub-mm) radio diagnostic of solar emission:
• give access to the highest energy particle accelerated during solar flares
(s = /B ~ 3 where B (Hz) = 2.8 106 B (Gauss))
• provide information on the dynamics of the lower solar atmosphere, below
the transition region (ff # Ne .T-3/2)
• increased spectral coverage
Particle Acceleration Radiation
Mechanisms
14th Solar-Terrestrial Physics Symposium – SCOSTEP – July 9-13, 2018, York University, Toronto, Canada
SOLAR FLARE PHYSICS:
INDICATION OF ANOTHER SOLAR BURST
CONTINUUM SPECTRUM IN THz
OBSERVATIONS IN THE THz RANGE ARE NEEDED TO UNDERSTAND THE EMISSION MECHANISMS INVOLVED
0.010.001
U-shaped spectrum (Castelli 1972)
Assumed as typical and common to all bursts
?
?
MHz
0.1 1.0 10.0 100.0
New solar burst spectral component(s)
observed in the THz range
THz
14th Solar-Terrestrial Physics Symposium – SCOSTEP – July 9-13, 2018, York University, Toronto, Canada
POEMAS
SST
SOLAR-T
30 THz
ALMA LLAMA HATS
BEMRAK
Radio Emission at very high frequencies: Flare Impulsive phase
Kaufmann et al. (2004; 2009) Luethi et al. 2004; Trottet et al. 2008; 2011); Silva et al. 2007; Raulin et al. (2003; 2004; 2014)
?? Sub-THz event ?? ?? Sub-THz event ?? Sub-THz event
Sub-mm impulsive radio emission associated with high-energy -ray continuum emission (CORONAS)
SST BEMRAK SST
Sub-THz event: increasing fluxes with increasing frequencies above 100 GHz
14th Solar-Terrestrial Physics Symposium – SCOSTEP – July 9-13, 2018, York University, Toronto, Canada
Radio Emission at very high frequencies
Trottet et al. 2008: Synchrotron
radiation by positrons from charged-
pion decay is likely to be too small to
account for the observed 210 GHz
emission (see also Silva et al.2007)
Radio source position ~ position of 2.2 MeV line
(Trottet et al. 2008)
2003/10/28
TransportTransport of secondary particles
Knock-on electrons (-rays) below few MeV
Not enough to explain 04/11/2003
(Tuneu et al. 2017)
14th Solar-Terrestrial Physics Symposium – SCOSTEP – July 9-13, 2018, York University, Toronto, Canada
HXR observations High-energy e- and p
transport energy to the lower layers
(chromosphere, photosphere) ?
30 THz emission another “THz event” ?
Genuine 30 THz (10 µm) solar emission during the impulsive phase of flare on 13/03/2012
(Initial results published in Kaufmann et al. 2013, ApJ)
12000 SFU
(Kaufmann et al. 2013)
Thermal emission from the chromosphere heated by accelerated particles provides a plausible
quantitative interpretation of the 30 THz emission during the impulsive phase.
SOL2012-03-13 is the first event detected at 30 THz.
HXR/GR are detected up to 10 MeV.
20 – 200 GHz radio spectrum is radiated by e- > 800 keV,
i.e. the harder part of the HXR/GR emitting distribution of e-.
(Trottet et al., 2015)
30 THz quiescent emission an optically thick layer at ~ 5000 K below the temperature minimum region.
30 THz flare emission is consistent with that expected from the F2 (Machado, Mauas) model: (i) 80%
optically thin source at ~ 8000 K well above the temperature minimum region; (ii) 20% optically thick
source below the temperature minimum region. In agreement with old models (Ohki & Hudson, 1975).
14th Solar-Terrestrial Physics Symposium – SCOSTEP – July 9-13, 2018, York University, Toronto, Canada
2014, Sept. 24, GOES C7, M. Penn
et al. (2016), McMath, NSO
McMath instrumental facilities observations +
measurements at 3 and 7 GHz by Solar-T (Kaufmann et
al., 2014) understanding of the chromospheric
response to flare energy release.
After Trottet et al. 2015, 10-100 THz
spectrum is expected to be rather flat.
Observations at > 30 THz (McMath-Pierce)
validated of such an expectation (Penn et al.,
2016).
14th Solar-Terrestrial Physics Symposium – SCOSTEP – July 9-13, 2018, York University, Toronto, Canada
• Results demonstrate that 3 and 7 THz SOLAR-T
photometers were responding well and were properly
calibrated
• Solar disk brightness fit fairly well to other observation
at a poorly known range of frequencies 4800 K and 4700
K at 3 THz and 7 THz
14th Solar-Terrestrial Physics Symposium – SCOSTEP – July 9-13, 2018, York University, Toronto, Canada
(Kaufmann et al. 2015)(Kaufmann et al. 2013)
(Penn et al. 2016)
(2017/09/06) (2011/02/14)
MIR flare emission versus
white-light
HATS: High Altitude Terahertz Solar telescope
(Simões et al. 2017)
0.871630 1.5 0.4 0.2
870 GHz, 1.5 THz
< 20% transmission at > 5000 m for PWV
<< 0.5 mm < 1 month/y
Opaque for PWV > 0.6 mm
Famatina (5500 m): characterization
16 THz ? OK at 2550 m, asl
~ 10s% temperature excess (OTTB)
LLAMA (first light 2019 ?)
SOLAR-T onboard ISS, accepted
14th Solar-Terrestrial Physics Symposium – SCOSTEP – July 9-13, 2018, York University, Toronto, Canada
Ionospheric Disturbances
Photons and/or energetic particles ionization excesses changes of the electrical conductivity
Localized particle precipitation
VLF propagation anomalies VLF phase and amplitude changes
Solar: quiescent, Ly-, X-rays (flares), particles (SEPs); Non-Solar: X-rays, GRB, flares from SGR
TGF
Few Mm
14th Solar-Terrestrial Physics Symposium – SCOSTEP – July 9-13, 2018, York University, Toronto, Canada
Transmitters (1-50 kHz)
Receivers
Solar flares can be detected over a large longitudinal sector
PLO
14th Solar-Terrestrial Physics Symposium – SCOSTEP – July 9-13, 2018, York University, Toronto, Canada
the higher the solar activity the
higher Px
Lyman- solar radiation maintains the quiet (non-disturbed) ionospheric D-region (Nicolet & Aikin 1960)
TRANSIENT SOLAR FORCING: FLARES
≥ B4 Class events are detected with 100
% probability
B Class C Class M Class
Ionospheric índice for the solar Ly- radiation
B 2.5
C 5
Fmin is well correlated with reproduces
the solar Lyman- photon flux
Photons and/or energetic particles ionization excesses changes of the electrical conductivity
VLF propagation anomalies VLF phase and amplitude changes
Solar: quiescent, Ly-, X-rays (flares), particles (SEPs); Non-Solar: X-rays, GRB, flares from SGR
14th Solar-Terrestrial Physics Symposium – SCOSTEP – July 9-13, 2018, York University, Toronto, Canada
14th Solar-Terrestrial Physics Symposium – SCOSTEP – July 9-13, 2018, York University, Toronto, Canada
(Palit et al. 2013)
(Palit et al. 2018)
- Photons versus particles
- Riometers of high latitude
- Photon energies
- ionosondes
Tshisaphungo and Danskin, 2016
The AFINSA network
*
operating
in 2017
+ Comandante Ferraz
Antarctic Station
(EACF)
(2)
https://theafinsa.wordpress.com/
Atmospheric Electric Field - GAEC
(Raulin et al. 2013)
GAEC
14th Solar-Terrestrial Physics Symposium – SCOSTEP – July 9-13, 2018, York University, Toronto, Canada
The AFINSA network https://theafinsa.wordpress.com/
Atmospheric Electric Field - GAEC
Superimposed method for
~ 150 solar flares Superimposed method
for 20 SEP events
14th Solar-Terrestrial Physics Symposium – SCOSTEP – July 9-13, 2018, York University, Toronto, Canada
Daily Atmospheric EF Excesses from fair weather curves
No detected effect ~ 10 % increase
Solar flare continuum observations from the mid-infrared domain (a few tens of THz) to the
millimeter-sub-millimeter radio domain provide in principle unique diagnostics of energy transport
processes from the flare energy release region to the chromosphere and of the most energetic
flare accelerated particles.
Solar Submillimeter Telescope (SST), KOSMA + BEMRAK and more recently high-cadence
imaging observations at 30 THz, SOLAR-T.
High frequency radio emissions in the mm- to submm- are produced by the highest energy
particles accelerated during solar flares: radiation processes, acceleration mechanisms
High frequency radio emissions in the mm- to submm- inform on the properties and the
dynamics of the cool and dense plasma in the chromosphere
Connection, if any, with mid-infrared emission spectrum is still not clear. MIR ? ? WL
OThinTB and OThickTB candidates to explain IR observations; chromospheric/photospheric
plasma heated by accelerated particles
More observations in the far- and mid-infrared are needed (HATS, Space SOLAR-T…)
The VLF technique provides a powerful diagnostic of the long-term and short-term solar activity,
including disturbances from cosmic bursts promising tool to study many aspects of the Space
Weather dynamics and provide Space Weather products
New diagnostics of solar energetic phenomena in the atmosphere of the Earth are available
Conclusions
14th Solar-Terrestrial Physics Symposium – SCOSTEP – July 9-13, 2018, York University, Toronto, Canada