Research Projects

Interactive Multi-Instrument Database for Studying Solar Flares 
(http://solarflare.njit.edu)

Viacheslav Sadykov, Rishabh Gupta, Alexander Kosovichev, Gelu Nita, Vincent Oria and Denis Akhmetov

Solar flares are the most powerful events in the Heliosphere. High-energy radiation and particles generated during the flares affect the Earth’s space environment, technological and biological systems. The radiation from the solar flares cover the whole range of electromagnetic spectrum, from radio- to gamma-rays, opening a broad observational opportunities for the space missions and ground-based observatories. We develop a multi-instrument database of solar flares. Our database integrates flare reports from various sources (e.g. GOES event list, RHESSI event list, SDO/HEK flares) and allows to group (match) the reports physically representing the same flare events based on their time and position on the solar disc. For the interaction with users, we have developed a web-based interface allowing the users to search events based on their physical characteristics (e.g. the flare duration, X-ray class temperature and emission measure etc.), browse them and identify the corresponding data products (GOES and SDO/EVE light curves, SDO images etc.). The database provides an important tool for studying the physics of solar flares and developing physics-based flare forecasts.
 

Integrated Global-Sun Model of Magnetic Flux Emergence and Transport

Alexander Kosovichev and Andrey Stejko

The proposal is a part of a large collaborative project led by Dr Nagi Mansour (NASA). The proposed effort of the NJIT in collaboration with Stanford helioseismology group will be focused on the development of helioseismology data analysis methods, helioseismology modeling and data assimilation for providing robust observational data and their interpretation for these objectives. This project includes the following tasks:
A. Detailed analysis of the cross-correlation function of solar oscillations for optimal detection of the emerging flux signal, development of a fast optimal measurement scheme and travel-time fitting method, investigation of systematic and random errors;
B. Statistical analysis of the emerging flux signals, determination of the emergence detection criteria and threshold, characterization of the emerging flux data in terms of the travel-time anomaly strength, spatial and temporal behavior, distortion of the cross-correlation function, and also in terms of the relationship to the structure, evolution and activity of magnetic region after the mergence;
C. Development of numerical MHD simulations of helioseismology data for realistic models of emerging magnetic flux (including variation of the thermodynamic parameters, magnetic field and associated plasma flows), validation and testing the helioseismology data analysis procedures and codes using the numerical simulation data;
D. Investigation of the relationship between the helioseismology results and emerging flux properties for constraining the models of emerging flux and determining the model state for mathematical data assimilation methods;
E. Improvement of far-side imaging technique by implementing and optimizing the time-distance helioseismology method; verification and testing of the far imaging by using the numerical MHD simulations; comparison with the traditional holography technique;
F. Characterization of the subsurface flow maps in terms of the magnetic flux transport, comparison with the surface flux transport data from correlation tracking analysis of magnetic features; determination of the meridional circulation and zonal flows; investigation of systematic and random errors and providing the flow data for the global MHD flux transport modeling.

 

Characterization of Sunquake Signatures in Terms of Energy and Momentum, and Their Relationship with the Flare Impulsive Phase

Alexander Kosovichev and Viacheslav Sadykov

The sunquakes, observed in the form of expanding wave ripples, in the solar photosphere represent packets of acoustic waves that are excited by flare impacts and travel through the solar interior. The excitation impacts strongly correlate with the impulsive flare phase and are caused by the energy and momentum transport from the flare magnetic energy released sites. However, the exact mechanism of the energy and momentum transport are not known. Solving the problem of the sunquake mechanism will substantially improve our understanding of the flare energy release
in the form of energetic particles, wave and mass motions and radiation. This project represents a comprehensive investigation of the sunquake properties and their relationship to the physical processes of the impulsive phase, using observational data from the SDO, RHESSI, Hinode, SOHO, and GONG, and numerical modeling.