Engineering topics

Tolbert, A. Kimberly

Publications and source records attributed to Tolbert, A. Kimberly.

3 records

NASA NTRS2007

Energetic Correlation Between Solar Flares and Coronal Mass Ejections

We find a strong correlation between the kinetic energies (KEs) of the coronal mass ejections (CMEs) and the radiated energies of the associated solar flares for the events that occurred during the period of intense solar activity between 18 October and 08 November 2003. CME start times, speeds, mass and KEs were taken from Gopalswamy et al. (2005), who used SOHO/LASCO observations. The GOES observations of the associated flares were analyzed to find the peak soft X-ray (SXR) flux, the radiated energy in SXRs (L(sub sxR)), and the radiated energy from the emitting plasma across all wavelengths (L(sub hot)). RHESSI observations were also used to find the energy in non-thermal electrons, ions, and the plasma thermal energy for some events. For two events, SORCE/TIM observations of the total solar irradiance during a flare were also available to give the total radiated flare energy (L(sub total)).W e find that the total flare energies of the larger events are of the same order of magnitude as the CME KE with a stronger correlation than has been found in the past for other time intervals.

Dennis, Brian R.↗

NASA NTRS2006

Correlated Flare and CME Energies for the October/November 2003 Events

We find a strong correlation between the kinetic energies (KEs) of the coronal mass ejections (CMEs) and the radiated energies of the associated solar flares for the events that occurred during the period of intense solar activity between 18 October and 08 November 2003. CME start times, speeds, mass, and KEs were taken from Gopalswamy et al. (2005), who used SOHO/LASCO observations. The GOES observations of the associated flares were analyzed to find the peak SXR flux, the radiated energy in SXRs (L(sub sxr)), and the radiated energy from the SXR emitting plasma across all wavelengths (L(sub hot)). RHESSI observations were also used to find the energy in non-thermal electrons, ions, and the plasma thermal energy for some events. For two events, SORCE/TIM observations of the total solar irradiance during a flare were also available to give the total radiated flare energy (L(sub total)). We find that the total flare energies of the larger events are of the same order of magnitude as the CME KE with a stronger correlation than has been found in the past for other time intervals. The following rule-of-thumb (good to an order of magnitude for the larger events} can be used to relate flare and CME energies: CME KE ~ l(sub total) ~ 10 L(sub hot) ~ 100 L(sub SXR).

Dennis, Brian R.↗

NASA NTRS2002

RHESSI and Trace Observations of the 21 April 2002 X1.5 Flare

Observations of the X1.5 flare on 21 April 2002 are reviewed using the Ramaty High Energy Solar Spectroscopic Imager (RHESSI) and the Transition Region and Coronal Explorer (TRACE). The major findings are as follows: 1. The 3-25 keV X-rays started 54 mins before the EUV (195 A) emission suggesting that the initial energy release heated plasma directly to 220 MK, well above the 1.6 MK needed to produce the Fe XII (195 A) line. 2. Using coaligned 12-25 keV RHESSI and TRACE images, further evidence is found for the existence of hot (15-20 MK) plasma in the 195 A passband. This hot, diffuse emission is attributed to the presence of the Fe XXIV (192 A) line within the TRACE 195 A passband. 3. The 12-25 keV source centroid moves away from the limb with an apparent velocity of approx. 9.9 km/ s, slowing to approx. 1.7 km/ s after 3 hours, its find altitude being approx. 120 Mm after approx. 12 hours. This suggests that the energy release site moves to higher altitudes in agreement with classical flare models. 4. The 50-100 keV emission correlates well with EUV flare ribbons, suggesting thick-target interactions at the footpoints of the magnetic arcade. The 50-100 keV time profile matches the time derivative of the GOES light curve (Neupert effect), which suggests that the same electrons that produced the thick-target hard X-ray emission also heat the plasma seen in soft X-rays. 5. X-ray footpoint emission has an E(sup -3) spectrum down to approx. 10 keV suggesting a lower electron cutoff energy than previously thought. 6. The hard X-ray (25-200 keV) peaks have FWHM durations of approx. 1 min suggesting a more gradual energy release process than expected. 7. The TRACE images reveal a bright symmetric front propagating away from the main flare site at speeds of greater than or = 120 km/ s. This may be associated with fast CME observed several minutes later by LASCO. 8. Dark sinuous lanes are observed in the TRACE images that extend almost radially from the post-flare loop system. This "fan of spines" becomes visible well into the decay phase of the flare and shows evidence for both lateral and downward motions.

Gallagher, Peter T.↗