Flare Luminosity and the Relation to the Solar Wind and the Current Solar

Minimum Conditions

Roderick GrayResearch Advisor:Dr. Kelly Korreck

Abstract

The Sun is an active and energetic star. From time to time, based on favorable magnetic structures, the Sun gives off bursts of energy in the form of particles and light. The light is commonly referred to as a solar flare, which is of great interest both scientifically as well as due to its relation to space weather. This project examined the luminosity in flares between Hinode's XRT, GOES and STEREO data to gain an understanding as to the energy budget of the flare as well as to the flare class that has already been used as a standard in space weather prediction. This is an important step to understanding the energy of the flare as well as the future of space weather prediction. It will be applicable to the soon to be launched SDO- AIA instrument which will observe the whole Sun full time.

Sun’s Magnetic Field Lines

Solar Flares Facts

Solar flare is an explosive release of energy that appear as a sudden, short lived brightening of an area in the chromosphere

A more powerful flare can produce a coronal mass ejection but coronal mass ejection can also happen without the presence of a flare

High Energy Flares can cause disturbances at Earth such as auroral displays, ground level particle events, electrical transmission power outages, and upper atmospheric altercations aswell

Soft X-Rays Classification

Space Weather Effects of Solar Flare Protons

The Solar Wind The solar wind is a stream of

particles that blows from the corona expanding into the interplanetary space, carrying a ceaseless flow of electrons, ions, and magnetic fields, after hitting the weakly ionized interstellar gaseous medium around 160 AU it is believed to begin to terminate

At Earth’s orbit about 1 AU the solar wind velocity usually ranges between 300-1400 km/s, the most probable value of solar wind is about 500 km/s which correlates to about a 4-day particle flight from the Sun to the Earth

Active regions have been identified as a potential source for the solar wind, it also emit X-rays, which are produced during magnetic reconnection events in the solar corona

There is a given linear relationship between X-Ray luminosity and the magnetic flux from the sun, which is describe by the equation:

Lx∝Φ1.13

Hinode X-RAY TELESCOPE

The Hinode X-Ray Telescope (XRT) is a high-resolution grazing-incidence telescope, which is a successor to the highly successful Yohkoh Soft X-Ray Telescope (SXT).[1]

A primary purpose of the Hinode XRT is to observe the generation, transport, and emergence of solar magnetic fields, as well as the ultimate dissipation of magnetic energy in forms such as flares and pico-flares, coronal heating, and coronal mass ejections [1]

Hinode consists of a set of three instruments: Solar Optical Telescope(SOT), Extreme ultraviolet Imaging Spectrometer (EIS), and X-RAY Telescope (XRT) instruments, of which XRT was used to calculate the Luminosity for the the active regions in the experiment

SOHO’s MDI

The magnetic flux in the active region was determined by using magnetograms from SOHO’s MDI instrument

The magnetic flux was calculated by the magentogram closest to the time of the flare as reported by GOES

The magnetic flux recorded in Maxwells was obtained by summing up a 512”X512” region of the magnetogram corresponding to the the field of view in XRT, in order to relate this quantity to the luminosity and solar wind power[2]

Ace Satellite

The Advanced Composition Explorer (ACE) spacecraft carries six high-resolution sensors and three monitoring instruments that samples low energy particles of solar origin and high energy galactic particles

ACE has a prime view of the solar wind, interplanetary magnetic field and higher energy particles accelerated by the Sun, as well as particles accelerated in the heliosphere

The ACE SWPAM (Solar Wind Electron, Proton, and Alpha Monitor) instrument was used to measure solar wind speed and density []

Connection between Flux and Luminosity

We use the formula provided by work from Schawdron, McComas & DeForest to find a connection between this unsigned magnetic flux and the Stereo EUV Data & X-Ray Luminosity

It describes the maximum power available for the solar wind since the available power can be reduced by chromospheric losses

Assuming that the injected electromagnetic energy-per-particle which powers the solar wind is constant, also the equation is observed by the constant magnetic reorganization of the low corona, suggesting that the upwelling energy flux at the solar wind source is proportional to the magnetic flux

Stereo EUV Data

STEREO is a 2 year mission of nearly identical spaced based observatories which can study the nature of the sun, more specifically coronal mass ejections at two different wavelengths

The corresponding flares are then done found in the Stereo 171 A & 195A, within 30 minutes before and after for a 512X512 image and also 2048X2048

The Total Data Number is then averaged, and converted to Luminosity by using the formula:DN AVG X (E)X 2*p*r2/ EFA

Magnetic Flux vs Luminosity

Lum

inos

ity (

erg

s-1)

Magnetic Flux (Mx)

=XRT

=171

=195

Luminosity and Power of Solar Wind vs Magnetic Flux

Lum

inos

ity (

erg

s-1)

=XRT

=171

=195

Referencs:

"Hinode is a Japanese mission developed and launched by ISAS/JAXA, with NAOJ as domestic partner and NASA and STFC (UK) as international partners. It is operated by these agencies in co-operation with ESA and the NSC (Norway).”[1]

Korreck et al (in preparation ApJ)[2]

http://www.srl.caltech.edu/ACE/[3]