Continuing data analysis of the AS/E grazing incidence X-ray telescope experiment on the OSO-4 satellite

The work to correct and extend the calculation of the theoretical solar X-ray spectrum produced during earlier OSO-4 data analysis is reported along with the work to formulate models of active regions, and compare these models with the experimental values. An atlas of solar X-ray photographs is included, and solar X-ray observations are correlated with the solar wind

Solar source regions of 3HE-rich particle events

Hydrogen alpha X-ray, and metric and kilometric radio data to examine the solar sources of energetic 3He-rich particle events observed near earth in association with impulsive 2 to 100 keV electron events were applied. Each 3He/electron event is associated with a kilometric type 3 burst belonging to a family of such bursts characterized by similar interplanetary propagation paths from the same solar active region. The 3He/electron events correlate very well with the interplanetary low frequency radio brightnesses of these events, but progressively worse with signatures from regions closer to the Sun. When H alpha brightnings can be associated with 3He/electron events, they have onsets coinciding to within 1 min of that of the associated metric type 3 burst but are often too small to be reported. The data are consistent with the earlier idea that many type 3 bursts, the 3He/electron events, are due to particle acceleration in the corona, well above the associated H alpha and X-ray flares

Fast drift kilometric radio bursts and solar proton events

Initial results of a comparative study of major fast drift kilometric bursts and solar proton events from Sep. 1978 to Feb. 1983 are presented. It was found that only about half of all intense, long duration ( 40 min above 500 sfu) 1 MHz bursts can be associated with F 20 MeV proton events. However, for the subset of such fast drift bursts accompanied by metric Type 2 and/or 4 activity (approximately 40% of the total), the degree of association with 20 MeV events is 80%. For the reverse association, it was found that proton events with J( 20 MeV) 0.01 1 pr cm(-2)s(-1)sr(-1)MeV(-1) were typically (approximately 80% of the time) preceded by intense 1 MHz bursts that exceeded the 500 sfu level for times 20 min (median duration approximately 35 min)

Coronal mass ejections, magnetic clouds, and relativistic magnetospheric electron events: ISTP

The role of high-speed solar wind streams in driving relativistic electron acceleration within the Earth\u27s magnetosphere during solar activity minimum conditions has been well documented. The rising phase of the new solar activity cycle (cycle 23) commenced in 1996, and there have recently been a number of coronal mass ejections (CMEs) and related “magnetic clouds” at 1 AU. As these CME/cloud systems interact with the Earth\u27s magnetosphere, some events produce substantial enhancements in the magnetospheric energetic particle population while others do not. This paper compares and contrasts relativistic electron signatures observed by the POLAR, SAMPEX, Highly Elliptical Orbit, and geostationary orbit spacecraft during two magnetic cloud events: May 27–29, 1996, and January 10–11, 1997. Sequences were observed in each case in which the interplanetary magnetic field was first strongly southward and then rotated northward. In both cases, there were large solar wind density enhancements toward the end of the cloud passage at 1 AU. Strong energetic electron acceleration was observed in the January event, but not in the May event. The relative geoeffectiveness for these two cases is assessed, and it is concluded that large induced electric fields (∂B/∂t) caused in situ acceleration of electrons throughout the outer radiation zone during the January 1997 event

Double Penguins and the Contribution of Vector Meson--like States to the Decays B→K∗γ, B→ργB \to K^* \gamma, \, B \to \rho \gamma

Using perturbative QCD, the contribution at the leading twist, leading $\alpha_s$ level, of charm and up quark loops to the decays $B \rightarrow K^* \gamma$ and $B \rightarrow \rho \gamma$ is presented. In the case of $B \rightarrow \rho \gamma$, the relative importance of these contributions depend upon the unknown CKM matrix elements $V_{bu}$ and $V_{td}$. Assuming that the ratio $r = V_{bc}V^*_{cd}/V_{bt}V^*_{td}$ is bounded between $-2.25 \le r \le -.5$ as is suggested by the Particle Data Group, the error in extracting $|V_{td}/V_{ts}|$ by these decays is estimated.Comment: 4 double column pages, revtex, 3 figures attached, 2 figures added indicating less optimism concerning the accuracy at which $|V_{td}/V_{ts}|$ can be extracted: to appear in PR

Does J/ψ→π+π−J/\psi \rightarrow \pi^{+} \pi^{-} fix the Electromagnetic Form Factor Fπ(t)F_{\pi}(t) at t=MJ/ψ2t=M_{J/\psi}^2?

We show that the $J/\psi \rightarrow \pi^{+} \pi^{-}$ decay is a reliable source of information for the electromagnetic form factor of the pion at $t=M_{J/\psi}^2=9.6 {\rm GeV}^2$ by using general arguments to estimate, or rather, put upper bounds on, the background processes that could spoil this extraction. We briefly comment on the significance of the resulting $F_{\pi}(M_{J/\psi}^2)$.Comment: 10 pages revtex manuscript, one figure--not included, U. of MD PP #94-00

Charge States of Solar Cosmic Rays and Constraints on Acceleration Times and Coronal Transport

We examine effects on the charge states of energetic ions associated with gradual solar flares due to shock heating and stripping at high ion velocities. Recent measurements of the mean charges of various elements after the flares of 1992 Oct 30 and 1992 Nov 2 allow one to place limits on the product of the electron density times the acceleration or coronal residence time. In particular, any residence in coronal loops must be for < 0.03 s, which rules out models of coronal transport in loops, such as the bird cage model. The results do not contradict models of shock acceleration of energetic ions from coronal plasma at various solar longitudes.Comment: 7 pages LaTeX + 2 tables in separate LaTeX file, necessary AAS macros are included, accepted by Astrophys. J. Let

Space Weather Application Using Projected Velocity Asymmetry of Halo CMEs

Halo coronal mass ejections (HCMEs) originating from regions close to the center of the Sun are likely to be responsible for severe geomagnetic storms. It is important to predict geo-effectiveness of HCMEs using observations when they are still near the Sun. Unfortunately, coronagraphic observations do not provide true speeds of CMEs due to the projection effects. In the present paper, we present a new technique allowing estimate the space speed and approximate source location using projected speeds measured at different position angles for a given HCME (velocity asymmetry). We apply this technique to HCMEs observed during 2001-2002 and find that the improved speeds are better correlated with the travel times of HCMEs to Earth and with the magnitudes ensuing geomagnetic storms.Comment: accepted for [publication in Solar Physic