D3.1
From Soteria
The present page is a template of how to fill in a deliverable report for the semiannual report.
To use this template, simply cut and paste it on the wiki page of your deliberable.
Lead Beneficiary: LPI
Beneficiaries involved: UNIGRAZ, KULeuven, ROB, OBSPARIS, SRC-PAS, UGOE, HVAR
Due Date: month 12
Contents |
Goal
The online report on results of the Task 3.5. It contains the results of the last and new multi-wavelength ground and space observations and theoretical modeling of solar activity processes associated with energy release (flares, CMEs), estimations of the magnetic flux and energy budgets for some selected events and analysis of their geo-space impact.
Successes
LPI , SRC-PAS
On January 30, the Russian CORONAS-PHOTON satellite was successively launched. It carries the TESIS EUV telescope/spectroheliograph and the SphinX spectrophotometer for studies of solar activity processes in the current 24th solar cycle. The first data were demonstrated at the Lapland meeting and will be used as the base for further analysis.
Exceptional Discoveries
Expected soon at increasing levels of solar activity.
Progress so far
LPI
A draft content of the online report has been composed and discussed within WP3. Contributions of all involved teams were defined. The list of selected events for analysis and numerical simulations was created and discussed within WP3 as well as with the WP4 teams.
Methods for the modeling of full-Sun monochromatic images in the XUV region obtained by the spectroheliograph RES aboard the CORONAS-F mission (tens of thousands spectroheliograms) along with other simultaneous XUV data (GOES, RHESSI) have been developed and used for a detailed study of physical conditions in coronal structures associated with active phenomena in the solar corona. Temperature content of the coronal plasma in the temperature range for log T(K) from 6.0 through 7.3 have been determined by means of temperature distributions of the DEM(T) have been derived for the first time from the EUV spectroheliograms in the region 176-207 and 280-330 A. Emission measure distribution were also inferred from the SXR monochromatic images in the resonance line of Mg XII ions (8.42 A) and simultaneous GOES and RHESSI data and the spectra of the X-ray sourses have been modeled and tested. The iterative Bayesian technique was developed and tested for the wide range of data on the basis of the last version of the CHIANTI database. The DEM(T) for different ARs and flares of different class and their temporal dynamics have been obtained and are at present a subject of detailed analysis. In active regions (AR) the presence of hot plasma with the temperature T>5 MK and a characteristic peak temperature of the DEM of about 10 MK, lasting from tens of minutes up to tens of hours have been discovered and its spatial and temporal properties were obtained. DEM(T) of plasma for all studied ARs were also revealed characteristic temperature peaks at 1.3 and 4 MK with EM comparable with that for hot component at the maximum of its luminosity. Strong correlation was shown between the heating of coronal loops and the topology of magnetic field structure. Long-duration hot plasma coronal loops are characterized by a complex structure of magnetic field and are shown to have the same energy release site during their heating and cooling. Simple systems magnetic loop structures with a few spots do not reveal long-duration heating. An intermediate transient plasma distributed in the temperature range 3-10 MK was shown to have a substantial contribution to the energy budget of long-duration events (LDE) – flares and post-eruptive phenomena. The space-time dynamics of the latter for so called “spiders”, firstly observed in Mg XII monochromatic images, with characteristic size up to 0.3 solar radius and time-life of ten hours was modeled. Having a steep temperature gradient comparable to that for impulsive events (IE) a slow density gradients was discovered with maximum density of 4 10^9 cm^-3 contrary to the value of two orders of magnitude larger for IE. Results are foreseen to be published in the Russian and international top journals with SOTERIA acknowledged.
The problem of particle acceleration in the solar corona has been studied in the framework of collapsing trap model by taking into account the particle scattering and braking in the high-temperature plasma of solar flares. The Coulomb collisions are shown to be weak in traps with lifetimes less than 10 s and strong for lifetimes more than 100 s. In the approximation of strong collisions, collapsing magnetic traps are capable of confining up to 20% of the injected particles in the corona for a long time. In the collisionless approximation, this value exceeds 90%. The question about the observational manifestations of collisions is examined. It’s shown that for collision times comparable to trap lifetimes, the electron spectra above 10 keV have double-power-law shape.
Acceleration of particles in flare reconnection site can be responsible for coronal hard X-ray source observed by RHESSI and Yohkoh. The coronal hard X-ray emission during solar flares can be interpreted under assumption that a fast plasma outflow from a reconnecting current sheet creates a shock wave above loops of strong magnetic field. It’s shown that this provides a new opportunity of particle acceleration: the two-step acceleration of electrons and ions. The first step is acceleration by the strong electric field present inside the current sheet. The second step is fast ‘adiabatic heating’ inside the collapsing magnetic trap. Both these mechanisms can efficiently increase the energy of energetic electrons created in reconnection site up to 1-5 MeV. The collapsing traps provide also favorable possibilities for acceleration of energetic protons and massive ions. Their energy after escape from the trap can reach 10-10 MeV depending on initial energy before acceleration and the particle’s mass. The numerical model of solar-energetic-particle (SEP) acceleration is now in development.
Persons involved: S. Kuzin, V. Slemzin, S. Bogachev, A. Urnov, A.Pertsov, A. Ignatiev, N. Sukhodrev, S, Shestov, F.Goryaev
KUleuven
2.5D viscous/resistive MHD simulations with compressive effects show that a current-sheet in the high Chromosphere/low Corona undergoes to a self-feeding mechanism [Lapenta 2008] driving the system from a slow to a fast reconnection regime [Bettarini & Lapenta 2008]. A final turbulent state is reached and this situation is a promising candidate to trigger solar explosive phenomena. Data point out the two-staged process comes with a significant release of accelerated plasma's structures and thermal energy distributed on turn in two steps during the fast regime: a slow increase in the energy fluxes (poynting, hentalpy, kinetic and momentum) followed by a impulsive event [Bettarini & Lapenta 2009] . This is characterized by a time scale of the order of 15 - 50 s and by the following physical values: mass flux ~ 0.8-2.4 x 10^(16) particle/cm^2 s; enthalpy flux ~ 0.6-7.2 x 10^7 erg/cm^2 s; kinetic flux ~ 1.7-22 x 10^7 erg/cm^2 s. Those values are consistent with observations of solar explosive phenomena [Tsuneta 1996, Shibata 1996]. References: Shibata, K. 1996, Adv. Space Res., 17, 9; Tsuneta, S. 1996, ApJ, 456, 840; Lapenta, G. 2008, Phys. Rev. Lett., 100, 235001; Bettarini, L. & Lapenta, G., 2009, ApJ., submitted Persons involved: G. Lapenta, L. Bettarini
HVAR, UNIGRAZ, OBSPARIS, ROB
Multi-wavelength observations of six flare/CME events were studied to infere whether the associated coronal shock was ignited by the flare or launched by the CME. The analysis of the kinematics of high-frequency radio type II bursts (recorded by the Astrophysikalisches Institut Potsdam and the Nancay Radio Helioghraph), kinematics of low-height signatures of CMEs (observed by LASCO-C1; EIT), and the evolution of the energy release in the associated flares, showed that in four events the shock was ignited by the flare. In two events the results are not decissive. The results are foreseen to be published in the journal Astronomy & Astrophysics (already in preparation). Persons involved: ROB (J. Magdalenic, Ch. Marque), HVAR (B. Vrsnak, T. Zic), UNIGRAZ (A. Veronig, M. Temmer), OBSPARIS (L. Klein), [non-soteria] AIP (H. Aurass).
UGOE
CME event list for 3D studies established. Flux rope models successfully applied and extended into the heliosphere based on STEREO/SOHO multipoint space observations. First CME tracked all the way along the Sun-Earth line (STEREO and ACE observations). Persons involved: V. Bothmer, A. Reiners.
SRC-PAS
The SRC-PAS Team has been busy with collecting and archiving the first-light data from the SphinX spectrophotometer, aboard Coronas-Photon. During first 50 days of active operation, the instrument collected ~30 GB of data, including small flares on March 26th. The data analysis of 30 Aug. 2002 and 14 Nov. 2002 flares is in progress. Results of complex analysis of selected flares including HD simulations of interaction between the non-thermal and thermal plasma components have been accepted for publication (A&A) with the SOTERIA acknowledged. Persons involved: J. Bakala, S. Gburek, A. Kepa, Z. Kordylewski, M. Kowalinski, P. Podgorski, M. Siarkowski, B. Sylwester, J. Sylwester, W. Trzebinski
Problem areas
The time schedule is tight, so we need to strengten actively the collaborations of all involved teams.
Suggestions for spin-off, collaboration or improvement
It is quite desirable to organize a short (1 day) meeting of involved people to discuss a draft of the report before summer vacations (possibly in July). Who may be the host? (Moscow is good place but not convenient because of visa problems).
