Local Flare Research Articles

Do All Flares Have White-Light Emission?

High-cadence, multiwavelength optical observations of a solar active region (NOAA 10969), obtained with the Swedish Solar Telescope, are presented. Difference imaging of white light continuum data reveals a white light brightening, 2 min in duration, linked to a co-temporal and co-spatial C2.0 flare event. The flare kernel observed in the white light images has a diameter of 300 km, thus rendering it below the resolution limit of most space-based telescopes. Continuum emission is present only during the impulsive stage of the flare, with the effects of chromospheric emission subsequently delayed by approximately 2 min. The localized flare emission peaks at 300% above the quiescent flux. This large, yet tightly confined, increase in emission is only resolvable due to the high spatial resolution of the Swedish Solar Telescope. An investigation of the line-of-sight magnetic field derived from simultaneous MDI data shows that the continuum brightening is located very close to a magnetic polarity inversion line. Additionally, an H-alpha flare ribbon is directed along a region of rapid magnetic energy change, with the footpoints of the ribbon remaining co-spatial with the observed white light brightening throughout the duration of the flare. The observed flare parameters are compared with current observations and theoretical models for M- and X-class events and we determine the observed white-light emission is caused by radiative back warming. We suggest that the creation of white-light emission is a common feature of all solar flares.

High-accuracy correction of critical dimension errors taking sequence of large-scale integrated circuits fabrication processes into account

We previously proposed a new method to correct critical dimension (CD) errors appearing in large-scale integrated circuit (LSI) fabrication processes, such as long range loading effect, local flare, and micro loading effect. The method provides high accuracy correction dimensions when using the pattern modulation method (method correcting CD errors by controlling figure sizes of LSI patterns). Now the case that several processes cause CD errors when a layer of an LSI pattern is fabricated on a wafer is discussed. These CD errors are corrected by generalizing the method proposed previously and taking the sequence of processes into account. It is shown from numerical calculation that the method can suppress the CD error to less than 0.01 nm with three iterations, under the condition that the maximum CD errors by micro loading effect and flare are 10 nm and 20 nm, respectively. It is strongly suggested that our methods will provide the necessary CD accuracies in the future.

Classification of undulated wavefront aberration in projection optics by considering its physical effects

Although wavefront aberration in stepper projection optics has been classified with respect to its spatial frequency on the pupil, the physical meaning of this classification has not been clarified. In this paper, we show that wavefront aberration can be classified into figure aberration, random aberration, and nonconserved aberration, by taking into consideration the theoretical effect of undulated wavefront aberration with respect to its spatial frequency. We also show that the predictions of this theoretical classification coincide with both the results of numerical simulations for random aberration and the experimentally measured values of local flare size. Since our classification has a clear physical meaning, it will be valuable and applicable in developing not only stepper projection optics but also other more general optics.

Printability of nonsmoothed buried defects in extreme ultraviolet lithography mask blanks

One of the most important challenges in extreme ultraviolet lithography is the need to provide mask blanks free of defects. In order to provide experimental results on the printability of buried defects, a dedicated extreme ultraviolet (EUV) mask blank was manufactured using ion beam sputtering (IBS) with a nonsmoothing process. Using this kind of process, the effect of the buried defect is apparent throughout the entire multilayer stack. The disturbance generated in the multilayer, measured using an atomic force microscope (AFM), shows lateral growth and a slight vertical smoothing effect. Here we report the printability results obtained with this kind of defect. One result concerns the influence of the defect density on the printability. We show that the major effect can be attributed to local flare, which depends on the pattern density. In order to better understand the printability mechanism of this kind of buried defect, we also compared the experimental results with electromagnetic simulation.

Novel via Chain Structure for Failure Analysis at 65 nm-Node Fixing OPC Using Inner and Outer via Chain Dummy Patterns

A novel via chain structure for failure analysis at 65 nm-node fixing OPC using inner and outer via chain dummy patterns has been proposed. The inner dummy is necessary to localize failure site in 200 nm pitch via chain using an optical beam induced resistance change method. The outer dummy protects via chain pattern from local flare and optical proximity effects. Using this test structure, we can identify the failure point in the 1.2k and 15k via chain fabricated by Cu/low-k single damascene process. This test structure is beneficial in the application to the 65 nm-node technologies and beyond.

Effects of flare in extreme ultraviolet lithography: Learning from the engineering test stand

One of the technical challenges for introducing extreme ultraviolet lithography (13.5 nm) into high volume manufacturing is flare. Flare reduces aerial image contrast and creates critical dimension (CD) variations across the die due to local chrome density dependent flare variations. Therefore, it is important to experimentally characterize flare on a full-field stepper and develop methods to mitigate and compensate for its effects. In this article, the impact of flare on depth of focus and exposure latitude are experimentally quantified using the engineering test stand. In addition, we report a marked increase in line width roughness due to high levels of flare in the optical system. A technique for the extraction of the point spread function due to scatter using density dependent CD data has been demonstrated for more accurate flare variation compensation.

Relativistic Iron Features from X-Ray Illuminated Spots and the Measure of the Black Hole Mass in AGN

Narrow spectral features in the 5-6 keV range were recently discovered in the X-ray spectra of a few Active Galactic Nuclei. We propose that these features originate from localized spots occurring on the surface of an accretion disc following its illumination by flares. Detailed calculations of the temporal and spectral properties of these features in our proposed model can be found in Dovciak et al. (2004). Comparison of the computed profiles with observed features can help to estimate parameters of the system. In principle this method can provide a powerful tool to measure the mass of super-massive black holes in Active Galactic Nuclei. By comparing our calculations with the Chandra and XMM-Newton results, we show, however, that spectra from present generation X-ray satellites are not of good enough quality to fully exploit the method and determine the black hole mass with sufficient accuracy. This task has to be deferred to future missions with both large sensitivity and high energy resolution, such as Constellation-X and Xeus. §1. The method Relativistic iron line profiles may provide a powerful tool to measure the mass of the black hole in Active Galactic Nuclei (AGNs) and Galactic black hole systems. To this aim, Stella (1990) proposed to use temporal changes in the line profile following variations of the illuminating primary source. Along the same line, Matt and Perola (1992) proposed to employ, instead, variations of the integrated line properties such as equivalent width, centroid energy and line width. These methods are very similar conceptually to the classical reverberation mapping method, widely and successfully applied to optical broad lines in AGNs. Sufficiently long monitoring of the continuum and of the line emission is however required, as well as large enough signal-to-noise ratio, and in practice these methods have not provided many results yet. A simple, direct and potentially robust way to measure the black hole mass would be available if the line emission originates at a given radius and azimuth, as expected if the disc illumination is provided by a localized flare just above the disc (possibly due to magnetic reconnection), rather than a central illuminator or an extended corona. If the resulting 'hot spot' co-rotates with the disc and lives for at least a significant part of an orbit, by fitting the light curve and centroid energy of

Correction for local flare effects approximated with double Gaussian profile in ArF lithography

A method has been developed for correcting line width variations due to midrange flare with a scattering range of over a few tens of micrometers (which we call local flare). It is shown that the conventional single Gaussian point spread function (PSF) is not sufficient and that a double Gaussian point spread function is needed to explain the line width variation caused by local flare. The remaining errors after correction are discussed under the assumptions that the mask correction is linear with respect to local flare intensity and is independent of pattern layout considering the order of the local flare correction (LFC) and optical proximity correction (OPC). This simple sizing method can reduce the critical dimension (CD) variation regardless of whether LFC is done before or after OPC. The LFC performance was evaluated using actual 90-nm-node LSI data. A much faster correction time than that of OPC was achieved by introducing the area density map method. The CD variation due to local flare was reduced from 22 to 5 nm.

Hflares from V404 Cyg in quiescence

We present a spectrophotometric study of short-term optical variability in the quiescent black hole X-ray transient V404 Cyg. This includes two nights of high-time-resolution Hα spectroscopy with which we resolve much of the time variability, and a further six nights of archival spectroscopy with lower time resolution but higher spectral resolution. We find significant variability in most of the data considered, with both the Hαline and the continuum often varying in a correlated way. This includes both dramatic flares lasting a few hours in which the line flux nearly doubles and lower-level flickering. The strongest flares involve development of asymmetry in the line profile, with the red wing usually strongest independent of orbital phase. It is unclear why this is the case, but we discuss several possible explanations. We consider the energetics of the flares and compare with plausible models including chromospheric activity on the companion star, local magnetic reconnection events within the disc and varying irradiation from close to the black hole. Based on the line profile changes during the flares, we conclude that the most likely origin for the variability is variable photoionization by the central source, although local flares within the disc cannot be ruled out.

Coronal mass ejections and emerging flux

This paper reviews our recent progress in the numerical study of coronal mass ejections (CMEs) based on flux rope model, which shows that when the reconnection-favored emerging flux appears either within or on the outer edge of the filament channel, the flux rope would lose its equilibrium, and be ejected, while a current sheet is formed below the flux rope. For the case with emergence within the filament channel, even small flux is enough to trigger the loss of equilibrium, however, there is a threshold for the emerging flux on the outer edge of the filament channel. Given that anomalous resistivity sets in (e.g. when the current density exceeds a critical value), fast reconnection is resulted in, leading to fast eruption of the flux rope and localized flare (either impulsive-type or LDE-type depending on the height of the reconnection point) near the solar surface. The numerical results can well explain why CMEs are not centered on flares and provide hints for CME-flare spatial and temporal relationships.

Anaphylaxis induced by horsefly bites: Identification of a 69 kd IgE-binding salivary gland protein from Chrysops spp. (Diptera Tabanidae) by western blot analysis

Anaphylaxis from insect venom is mostly caused by Hymenoptera stings but has been also reported after bites by various blood-feeding arthropods. The horseflies (Tabanidae, comprising some taxonomically poorly defined subgroups such as deerflies, yellowflies, or clegs) is a hematophagous family of Diptera, with several species that feed on human beings. Bites by tabanids are painful and may induce a local wheal and flare response. However, they have also been believed to cause severe systemic reactions.

Contact Urticaria Syndrome: 1997

Contact urticaria syndrome (CUS) consists of a heterogeneous group of vascular and inflammatory reactions that occur within minutes to an hour of contact with a causative agent. Reactions can vary from a localized wheal and flare, to more systemic aspects – asthma, anaphylaxis, and even death – depending upon the agent and patient response. The breadth of eliciting agents and incidence of CUS has been growing as awareness of the syndrome has developed, although the true scope of the syndrome in the general population remains uncertain due to a lack of epidemiological information. Diagnosis has historically been and remains difficult, as reactions typically disappear within hours and before patients even meet with a healthcare worker. As a result, detailed patient histories and immediate type allergy testing are the primary modes of diagnosis. Treatment consists primarily of awareness and agent avoidance. Extreme cases may require patients to wear a bracelet detailing their allergies, and possibly carry antihistamines or self-administered epinephrine.

Postherpetic neuralgia. Are C-nociceptors involved in signalling and maintenance of tactile allodynia?

Under normal conditions acute stimulation and sensitization of polymodal nociceptive C-fibres cause pain and, due to afferent axon reflex activation, a local skin vasodilatation, flare reaction and skin temperature increase. Two questions arise: (i) Do sensitized C-nociceptors signal allodynia in chronic postherpetic neuralgia? (ii) If not, does ongoing peripheral nociceptive C-fibre input maintain a central process that accounts for allodynia? Ten patients with postherpetic neuralgia and tactile allodynia and 10 control subjects were studied using a laser Doppler perfusion monitor. Peripheral nociceptive C-fibre function was assessed by quantitative measurement of the axon reflex vasodilatation and flare reaction induced by histamine iontophoresis and compared with non-neural vasodilatation induced by local skin heating. Resting skin temperature, skin resistance and resting skin blood flow were the same in the allodynic area and the contralateral homologous skin area. The histamine responses (vasodilatation and flare) were significantly reduced or nearly abolished in the allodynic area compared with the contralateral side, whereas the temperature-dependent vasodilatation in patients and the histamine responses in healthy controls showed no side differences. C-fibre mediated pain and itch sensations were also decreased in the allodynic area. These findings indicate a considerable impairment of cutaneous nociceptive C-fibre function in the allodynic area. Allodynic stimuli of 20 s did not cause any local blood flow change. Impairment of C-fibre function was positively correlated with intensity of neuropathic pain. We conclude that sensitized nociceptive C-fibres are not involved in signalling allodynia. Changes in CNS processing may occur after zoster infection that strengthen the synaptic ties between central pain signalling pathways and low-threshold mechanoreceptors with A beta-fibres. This altered central processing is not maintained by ongoing cutaneous nociceptive C-fibre input, at least in some patients with postherpetic neuralgia. On the contrary, an anatomical synaptic reorganization depending on afferent C-fibre degeneration seems to be more likely, particularly in advanced stages of postherpetic neuralgia.

Synovial sarcoma manifesting as a single joint flare in rheumatoid arthritis

A 69-year-old female recently diagnosed as suffering from rheumatoid arthritis presented with a general flare-up of disease including a swollen left ankle. Investigation revealed the swelling to be due to a synovial sarcoma. This unusual cause should be considered in all cases of local joint flares in rheumatoid arthritis.

Safety of latex prick skin testing in allergic patients

<h3>In Reply.</h3> —This is not the first patient reported to have a possible anaphylactic reaction with the latex prick skin test.¹Any potent allergen skin test in exquisitely sensitive patients has this risk. The latex testing extract is properly labeled as "may cause anaphylaxis." However, if properly done, the latex prick skin test is very safe. We have safely skin tested 115 patients,^2,320 of whom had severe latex allergy. Our experience agrees with that of others.⁴The skin test needs to be carefully watched and immediately wiped clean with isopropyl alcohol after a positive result. This may be as soon as 5 to 7 minutes after the test. I question whether the patient reported by Bonnekoh and Merk had an anaphylactic event. There was minimal local reaction at the test site and, in patients with anaphylaxis, we generally see a large local wheal and flare. The

Safety of Latex Prick Skin Testing in Allergic Patients-Reply

In Reply. —This is not the first patient reported to have a possible anaphylactic reaction with the latex prick skin test.1Any potent allergen skin test in exquisitely sensitive patients has this risk. The latex testing extract is properly labeled as cause anaphylaxis. However, if properly done, the latex prick skin test is very safe. We have safely skin tested 115 patients,2,320 of whom had severe latex allergy. Our experience agrees with that of others.4The skin test needs to be carefully watched and immediately wiped clean with isopropyl alcohol after a positive result. This may be as soon as 5 to 7 minutes after the test. I question whether the patient reported by Bonnekoh and Merk had an anaphylactic event. There was minimal local reaction at the test site and, in patients with anaphylaxis, we generally see a large local wheal and flare. The

Wheal and Flare Responses to Opioids in Humans

Certain opioids release histamine from cutaneous mast cells to produce local wheal and flare responses and adverse hemodynamic effects. In vivo responses to opioids suggest that cutaneous responses result from the interaction of opioids with opioid receptors on human mast cells. There are no data evaluating or comparing the opioids currently used in anesthesia. Volunteers were injected intradermally with different opioids as well as with naloxone and antihistamines to evaluate their effects on cutaneous mast cell reactivity and cutaneous vascular responses. Fentanyl and morphine produced concentration-dependent wheal and flare responses in the range of 5 X 10(-6) M to 1.5 X 10(-3) M. Volunteers were then tested intradermally with different opioids and histamine at a 5 X 10(-4) M concentration to determine their relative cutaneous effects. Morphine, meperidine, fentanyl, and sufentanil produced both wheal and flare responses that were significantly greater than those due to saline (P less than 0.05). Naloxone, alfentanil, and nalbuphine did not produce significant wheal or flare responses. Butorphenol was followed by a significant wheal but no flare. Naloxone attentuated cutaneous wheal and flare responses to fentanyl and the flare response to morphine. Intradermal antihistamines (diphenhydramine and cimetidine) produced significant wheal and flare responses. Electron micrographs of biopsies from fentanyl-induced wheals demonstrated normal mast cell architecture with no evidence of mast cell degranulation. Opioid effects on wheal and flare responses and mast cell degranulation appear independent of opioid analgesic potency. Opioids produce cutaneous vascular responses dependent on both histamine release from mast cells and direct effects on the vasculature.(ABSTRACT TRUNCATED AT 250 WORDS)

Interleukin 2 and Psoriasis

Immunotherapy with interleukin 2 and lymphokine-activated killer cells can result in regression of metastatic cancer. Dermatologic complications associated with this therapy include erythema, pruritus, and a mild desquamation. Three patients with a history of psoriasis received high-dose interleukin 2 alone or in conjunction with lymphokine-activated killer cells for treatment of metastatic renal cell carcinoma. Two patients developed an erythrodermic exacerbation during therapy while the third patient experienced a localized flare. Topical treatment was effective in inducing remission in all three patients. Histologic analysis of serial skin biopsy specimens revealed psoriasiform changes in involved skin as well as epidermal spongiosis and a perivascular mononuclear cell infiltrate. The psoriatic exacerbation from interleukin 2 did not affect antitumor response to the therapy and should not be considered a contraindication to treatment.

Permanent flare activity in the magnetosphere during periods of low magnetic activity in the auroral zone

Auroral, magnetic variation and pulsation data from the dense network in the nearmidnight portion of the auroral zone are used together with the measurements of suprathermal particles and electromagnetic fields by the IMP-8 and ISEE-1 spacecraft within the plasma sheet to study the characteristics of activity during two magnetically quiet periods on 3 March 1976 and 23 March 1979. Contrary to existing beliefs, we found clear signatures of numerous (5–10 events per hour) transient events, characterized by plasma flows, energetic particle bursts and E− B field variations. A close association of these events in the plasma sheet with the local auroral flares (LAFs) in the conjugate sector of the auroral zone is established for many events. We conclude that LAF (local auroral arc activation with associated Pi pulsations but extremely weak magnetic bays) have the same plasma sheet manifestations (apparently, the same physics) as the individual substorm intensifications during strong substorm expansion events, which differ from the studied quiet periods mainly by the strength and number of these intensifications. These transient phenomena seem to play an important role in the energetics of the quiet time magnetotail.

Brass Instrument Design and the Theory of Horns

Engineering the design of horns has been chiefly directed toward transducer applications, where freedom from resonances and a low cutoff frequency are desirable. In the musical horns, easy oscillation and good tuning both call for a high cutoff frequency and accurately placed resonances. The radiation load must not be more than a perturbation at playing frequencies. Horns of rapid flare are required, for which plane-wave theory is inadequate. The “reduced” pressure wave function ψ(z) (=pS12) is mathematically and conceptually convenient, where S(z) is the area of the spherical wavefront at the point z along the horn axis. The “reduced” spherical wave equation ψ″+[k2−U(z)]ψ = 0 (studied by Jansson) is tractable, the horn function U being easily visualized in terms of the transverse and longitudinal curvatures of the horn. Exact solution of the equation is not always required, since useful estimates of U can be made by inspection, whence calculations related to phase integrals, plus perturbation theory permit excellent approximations to the resonance frequencies. Different perturbation methods are useful along the horn depending on local flare. Preexisting horns may be diagnosed and corrected on the basis of laboratory data or “musicians' experiments.” Practical examples will be discussed.