Monday, May 4, 2015

High-Temperature Lines in SUMER Spectra Recorded Above a Bright Solar Active Region

THE ASTROPHYSICAL JOURNAL, 503:467–474, 1998 August 10
© 1998. The American Astronomical Society. All rights reserved. Printed in U.S.A.



High-Temperature Lines in SUMER Spectra Recorded Above a Bright Solar Active Region

U. FELDMAN, 1 W. CURDT, 2 G. A. DOSCHEK, 1 U. SCHÜHLE, 2 K. WILHELM, 2 AND P. LEMAIRE 3

Received 1997 October 16; accepted 1998 March 12


ABSTRACT

     We identify spectral lines emitted by solar abundant elements due primarily to transitions within the 2s22pk and 3s23pk (where k = 1, 5) ground configurations of ions that are formed in ionization equilibrium between 2 × 106 and 8 × 106 K. The transitions were identified in spectra of a bright active region recorded 1997 September 6, by the Solar Ultraviolet Measurements of Emitted Radiation Spectrometer (SUMER) flown on the Solar and Heliospheric Observatory (SOHO). Some of these lines provide useful plasma diagnostic tools for measuring the physical conditions in the solar corona.
Subject headings: line: identifications—Sun: corona—Sun: UV radiation

FOOTNOTES

     1 E. O. Hulburt Center for Space Research, Mail Code 7608, Naval Research Laboratory, 4555 Overlook Avenue SW, Washington DC, 20375-5352.
     2 Max-Planck-Institut für Aeronomie, D-37191 Katlenburg-Lindau, Germany.
     3 Institut d'Astrophysique Spatiale, Unite Mixte Centre Nationale de la Recherche Scientifique, Université Paris XI, Bat 121, F-91405 Orsay, France.

§1. INTRODUCTION

     In a recent paper Feldman et al. (1997, hereafter Paper I) published an extensive list of spectral lines in the 500–1610 Å range compiled from spectra recorded 1996 June 25 by the Solar Ultraviolet Measurements of Emitted Radiation Spectrometer (SUMER) flown on the Solar and Heliospheric Observatory (SOHO). The spectra were recorded at a height of about 20,000 km above the west equatorial solar limb. Curdt et al. (1997) also published a line list from a SUMER solar disk spectrum that covers the 660–1175 Å range. However, from the time that SOHO was launched until recently conditions on the Sun have been typical of solar minimum. Active regions have been scarce and small, and therefore only a few of the brightest lines characteristic of plasmas with temperatures Te > 1.5 × 106 K are visible in SUMER spectra of these regions, and consequently only a few such lines are tabulated in the published line lists. Recently, however, as the Sun has become increasingly more active, more lines emitted by higher temperature plasmas have appeared in SUMER active region spectra.
     The main allowed lines (electric dipole transitions) emitted by highly ionized ions that are present in high-temperature (Te > 2 × 106 K) solar coronal plasmas appear at short wavelengths (λ < 500 Å) not accessible to the SUMER instrument. However, a number of forbidden transitions arising from levels that do not decay via electric dipole transitions are calculated to be bright in high-temperature solar plasmas and are expected to be present in the SUMER spectral range. These lines arise mainly from transitions within the 2s22pk and 3s23pk (where k = 1, 5) ground configurations. Since bright forbidden lines emitted by lower temperature plasmas (Te < 2 × 106 K) are prominent in quiet-Sun SUMER spectra (Paper I), we expect to see similar high-temperature forbidden lines from the solar abundant elements Ar, Ca, Fe, and Ni in active region spectra.
     In this paper we report the identification of spectral lines emitted by plasmas with temperatures between 2 × 106 K that are useful for determining emission measure distributions, electron densities, and mass motions above bright active regions. Except for the 1133.76 Å Ca XIII line, which is present in the Curdt et al. (1997) list, none of the lines is normally seen in disk spectra. Some of the newly identified lines at wavelengths short of 680 Å and those in the 937–1361 Å range are also expected to be observed under certain coronal conditions at heights greater than 1.5 R&sun; by the SOHO Ultraviolet Coronagraph Spectrometer (UVCS; Kohl et al. 1995). Several of the lines should also be visible in spectra obtained by the SOHO Coronal Diagnostic Spectrometer (CDS; Harrison et al. 1995). Flare lines that are expected to be seen at temperatures greater than 8 × 106 K have not yet been seen by SUMER. However, lines of Fe XVIII and Fe XIX have been observed and are discussed in this paper.

§2. SUMER SPECTROMETER AND OBSERVATIONS

     The SUMER spectrometer is a high spectral and spatial resolution slit spectrometer. The wavelength range for the detector used to obtain the present observations (detector B) is 660–1500 Å in first order and 500–750 Å in second order. The slit of the spectrometer is usually oriented in the north–south direction (occasionally it has been in the east-west direction during SOHO roll maneuvers). Five available slits can be used. For the spectra discussed in this paper the slit size was 4 × 300 arcsec2. The spatial resolution along the length of the slit is about 1&arcsec;. The spectral dispersion is about 43 mÅ pixel-1 in first order and 22 mÅ pixel-1 in second order. Spectra are recorded by one or two microchannel plate photon counting detectors. Each detector views a 44 Å window (first order) from the overall wavelength range that is selected using a movable plane scan mirror. The instrument is described in detail by Wilhelm et al. (1995), and first results are described by Wilhelm et al. (1997) and Lemaire et al. (1997).
     The spectra used to identify the spectral lines are a set of 300 s exposures recorded 1997 September 6 between about 01:04 and 06:42 UT. The spectra are part of the "reference spectrum" program, i.e., full wavelength coverage spectra are periodically recorded for many different types of solar regions and at different locations. On this day the solar radius was 962&arcsec;. The pointing for these reference spectra was located above an active region on the north-west limb. The slit was oriented in the north-south direction with the center of the slit located 960&arcsec; west and 370&arcsec; north of Sun center. The limb distance varied between 22&farcs;7 (bottom/south of the slit) and 129&farcs;6 (top/north of the slit). This was the site of active region NOAA 8076 that flared on September 5. An image of the region obtained by the Extreme Ultraviolet Imaging Telescope (EIT) on SOHO is shown in Figure 1.
Fig. 1

§3. SPECTRAL ANALYSIS

     A spectral line list with all the new identifications including wavelengths and transitions is given in Table 1. The wavelengths are believed to be accurate to ±0.02 Å. The wavelengths were derived from the spectra after the spectra were flat-field corrected and the geometric distortions were removed ("destretched"). The intensities were obtained from a single active region reference spectrum. Because this spectrum took several hours to record, and active regions exhibit considerable transient behavior, intensity ratios of lines at widely separated wavelengths may not be accurate.
     Six of the forbidden lines are shown in Figures 2 and 3. In Figure 2, an active region spectrum is compared with a quiet-Sun spectrum. Note the presence of Ca XIII, Ca XIV, and Ca XV lines in the active region spectrum and their absence in the quiet-Sun spectrum. In Figure 3, an Fe XIX flare line is shown. Note that the flare line shows substantial Doppler broadening and that it is confined to the small spatial regions of the flare.
Fig. 2 Fig. 3      We discuss the methods of identification in this section. Forbidden transitions in ions of neon to sulfur and in Ar XI having maximum fractional abundance temperatures less than 2 × 106 K are present in the SUMER wavelength range and were discussed in an earlier publication (Paper I). Two forbidden transitions from Ar XII, although quite faint, were also seen in the quiet-Sun spectra and were discussed in Paper I. We report new identifications of Ar XIII, Ar XII, Ca XV, Ca XIV, Ca XIII, Ni XV, and Ni XIV forbidden lines, and the transitions are given in Table 1. Using a semi-empirical method, Edlén predicted the energy levels within the ground configurations of the ions (Edlén 1983, 1984, 1985).

§3.1. The Ar XIII Spectrum

     The maximum fractional abundance of Ar+12 is at 2.5 × 106 K (Arnaud & Rothenflug 1985). The 2s22p2 ground configuration includes the following levels: 3P0,1,2, 1D2, and 1S0. Two of the forbidden transitions within the ground configuration, i.e., 3P1–1D2 (1330.54 Å) and 3P1–1S0 (656.69 Å), are predicted to be in the SUMER detector B wavelength range. The other bright forbidden lines resulting from transitions within the ground configuration are at longer wavelengths and are not accessible with SUMER. A previous identification of the 3P1–1D2 transition (Sandlin, Brueckner, & Tousey 1977) is in error. Both the 1330.54 and 656.69 Å lines are observed for the first time in the SUMER active region spectra. Details concerning the Ar XIII energy levels are given in Table 2. The energies of the 3P1 and 3P2 levels are taken from Edlén (1985).

§3.2. The Ar XII Spectrum

     The maximum fractional abundance of Ar+11 is at 2.1 × 106 K (Arnaud & Rothenflug 1985). The 2s22p3 ground configuration includes the following levels: 4S3/2, 2D3/2,5/2, and 2P1/2,3/2 (see Fig. 4). Edlén (1984) predicted the energies of the levels within the ground configuration of Ar+11. Four of the forbidden transitions within this configuration, i.e., 4S3/2–2D3/2(1054.62 Å), 4S3/2–2D5/2(1018.87 Å), 4S3/2–2P1/2(670.34 Å), and 4S3/2–2P3/2(648.93 Å), are predicted to be in the SUMER detector B wavelength range. The other transitions are at longer wavelengths and are not accessible with SUMER. The 1054.57 and 1018.87 Å lines were seen before in the SUMER quiet-Sun spectra (Paper I) where they were quite weak. The 670.34 Å transition is observed for the first time in the active region spectra. The 648.93 Å transition is most likely present in the spectra but is blended with the bright 649.20 Å Si X line. Details concerning the Ar XII energy levels are given in Table 3.
Fig. 4

§3.3. The Ca XV Spectrum

     The maximum fractional abundance of Ca+14 is at 3.5 × 106 K (Arnaud & Rothenflug 1985). The 2s22p2 ground configuration includes the following levels: 3P0,1,2, 1D2, and 1S0. Edlén (1985) predicted the energies of the levels within this configuration. Only two of the forbidden transitions within the ground configuration, i.e., 3P2–1D2 (1375.96 Å) and 3P1–1D2(1098.44 Å), are visible in the SUMER detector B wavelength range. The 3P1–1S0 transition expected to appear at 555.21 Å is not visible, most likely due to the low reflectivity of SUMER at that wavelength. The 1122.7 Å 1D2–1S0 transition is not visible, and all other transitions are at longer wavelengths. The 1375.96 Å line was previously observed in Skylab spectra by Feldman & Doschek (1977) and Sandlin et al. (1977). Details concerning the Ca XV energy levels are given in Table 2. The energies of the 3P1 and 3P2 levels are taken from Edlén (1985).

§3.4. The Ca XIV Spectrum

     The maximum fractional abundance of Ca+13 is at 3.0 × 106 K (Arnaud & Rothenflug 1985). The 2s22p3 ground configuration includes the following levels: 4S3/2, 2D3/2,5/2, and 2P1/2,3/2 (see Fig. 4). Edlén (1984) predicted the energies of the levels within the configuration. Six of the forbidden transitions within the ground configuration, i.e., 4S3/2–2D3/2(943.61 Å), 4S3/2–2D5/2(880.43 Å), 4S3/2–2P1/2 (579.85 Å), 4S3/2–2P3/2(545.26 Å), 2D3/2–2P3/2(1291.61 Å), and 2D5/2–2P3/2(1432.12 Å), are predicted to be in the SUMER detector B wavelength range. The 2D3/2–2P1/2 transition is predicted to be at 1503.1 Å. This wavelength is outside the SUMER B detector range, but the line is expected to be visible in the wavelength range of detector A. All but the 1432.12 Å are seen in the SUMER spectra. Details concerning the Ca XIV energy levels are given in Table 3.

§3.5. The Ca XIII Spectrum

     The maximum fractional abundance of Ca+12 is at 2.5 × 106 K (Arnaud & Rothenflug 1985). The 2s22p4 ground configuration includes the following levels: 3P2,1,0, 1D2, and 1S0. Edlén (1983) predicted the energies of the levels within the configuration. Only two of the forbidden transitions within the ground configuration, i.e., 3P2–1D2 (1133.79 Å) and 3P2–1S0(648.68 Å), are predicted to be in the SUMER detector B wavelength range. All other transitions are at longer wavelengths. Both transitions are present in the active region data (Table 1). The 1133.79 Å line was seen before as a very faint feature in Skylab flare spectra (Feldman & Doschek 1991). Details concerning the Ca XIII energy levels are given in Table 4. The energies of the 3P0 and 3P1 are taken from Edlén (1983).

§3.6. Fe XVII, FeXVIII, and FeXIX Forbidden Transitions

     Four highly ionized iron transitions emitted by Fe XVII, Fe XVIII, and Fe XIX are also present in active region spectra. The maximum fractional abundance of Fe+16 is at 4.0 × 106 K, Fe+17 is at 6.3 × 106 K, and Fe+18 is at 7.9 × 106 K (Arnaud & Raymond 1992). The 1153.16 Å Fe XVII (2s22p53s 3P1–2s22p53s 3P0) and the 974.86 Å Fe XVIII (2s22p5 2P3/2–2s22p5 2P1/2) lines are bright in the active region spectra, whereas the 592.2 Å Fe XIX (2s22p4 3P2–2s22p4 1D2) and 1118.08 Å Fe XIX (2s22p4 3P2–2s22p4 3P1) lines are fairly faint. All four transitions were previously observed in Skylab solar flare spectra (Doschek et al. 1975; Sandlin et al. 1977; Dere 1978; Feldman, Doschek, & Seely 1985; and Feldman & Doschek 1991). The Fe XVIII line and the long-wavelength Fe XIX line are also observed in Tokamak spectra (Peacock, Stamp, & Silver 1984). The SUMER spectral range contains additional forbidden lines from Fe XIX, Fe XX, Fe XXI, and Fe XXII which are expected to be present in spectra dominated by flare plasmas. The Fe XXI line at 1354.1 Å is well-known in flare spectra. It was seen in Skylab spectra by Doschek et al. (1975) and was discussed by many subsequent investigators using spectra from the Solar Maximum Mission and rocket experiments. It is also observed in stellar spectra (Maran et al. 1994). The Fe XXII line at 845.1 Å was reported in an Orbiting Solar Observatory flare spectrum by Noyes (1973).

§3.7. Ni XIII, Ni XIV, and Ni XV Forbidden Transitions

     We observe one Ni XIII line previously reported in solar spectra by Sandlin et al. (1977). Three highly ionized nickel transitions belonging to Ni XIV and Ni XV are present in the active region spectra. The maximum fractional abundances of Ni+13 and Ni+14 are at 2.1 × 106 and 2.3 × 106 K, respectively (Arnaud & Rothenflug 1985). The 1034.48 Å Ni XIV (3s23p3 4S3/2–3s23p3 2P3/2) line, the 1174.65 Å Ni XIV (3s23p3 4S3/2–3s23p3 2P1/2) line, and the 1033.04 Å Ni XV (3s22p2 3P1–3s23p2 1S0) line are very prominent in the spectrum. The 1174.65 Å line was first seen in Skylab spectra and was reported to be at 1174.72 Å (Sandlin et al. 1977). Predicted wavelengths for the nickel forbidden lines were taken from Kaufman & Sugar (1986).

§4. DENSITY SENSITIVE LINE RATIOS

     Forbidden transitions within the ground configuration of the N I isoelectronic sequence are suitable density indicators for solar plasmas. Feldman et al. (1978) showed that intensity ratios between the 2s22p3 4S3/2–2s22p3 2D3/2 and 2s22p3 4S3/2–2s22p3 2D5/2 transitions, and between the 2s22p3 4S3/2–2s22p3 2P3/2 and 2s22p3 4S3/2–2s22p3 2D3/2 transitions in Mg VI, Si VIII, and S X, and to a certain extent in Ar XII, can provide a good measure of the electron density in various regions of the corona. They were able to use the S X lines in Skylab spectra to derive densities. Subsequently, the first mentioned line ratio has been used by Doschek et al. (1997) and Laming et al. (1997) to derive densities in polar coronal holes and quiet-Sun regions using SUMER spectra.
     The above transitions in Ar XII and in particular in Ca XIV are most suitable for probing the electron density of dense and hot active regions. As shown in Figure 5, the various Ar XII forbidden line ratios are sensitive to densities between 109 and 1012 cm-3. The identical transitions in Ca XIV are sensitive to densities between 1010 and 1013 cm-3. Intensity ratios between the 2s22p2 3P1–2s22p2 1D2 and the 2s22p2 3P1–2s22p2 1S0 transitions in Ar XIII and between the 2s22p4 3P2–2s22p4 1D2 and the 2s22p4 3P1–2s22p4 1S0 transitions in Ca XIII are sensitive to the electron densities that vary between 1010.5 and 1013 cm-3. The density sensitivity of Ar XIII and Ca XIII is shown in Figure 6.
Fig. 5 Fig. 6      The above discussion is included to demonstrate to readers the diagnostic importance of some of the forbidden lines. We have attempted to obtain densities for the active region from which the intensities in Table 1 were derived, but we obtain inconsistent results, i.e., we derive densities that differ by more than seems reasonable based on inaccuracies in the atomic physics of line excitation. This is likely due to time variability of the line intensities. The SUMER observations were not optimized for obtaining densities using the forbidden lines, but a good observational sequence could easily be constructed.

ACKNOWLEDGMENTS

     The SUMER project is financially supported by DARA, CNES, NASA, and the ESA PRODEX program (Swiss contribution). The Naval Research Laboratory contribution to this work was supported by NRL/ONR basic research funds, by the SOHO Project, and by a NASA SR&T grant (W-18218) to one of us (G. A. D.). We would like to thank Catherine Abbott for her help in reducing the SUMER data and we thank Martin Laming for providing the density sensitivity calculations.

REFERENCES

FIGURES


Full image (388kb) | Discussion in text
     FIG. 1.—EIT image of the 1997 September 6 active region

Full image (244kb) | Discussion in text
     FIG. 2.—Forbidden lines of Ca in an active region spectrum. Note that they are absent in the quiet-Sun spectrum included for comparison.

Full image (391kb) | Discussion in text
     FIG. 3.—Spectrum showing the Fe XIX flare line near 1118 Å. Top: a tracing through the spectrum; bottom: distribution of emission along the slit length. Note the small regions in which the Fe XIX emission is confined and the large Doppler motions shown by the spectral width of the lines.

Full image (61kb) | Discussion in text
     FIG. 4.—Energy levels (cm-1) and transitions (Å) for Ar XII (in parentheses) and Ca XIV detected by SUMER.

Full image (69kb) | Discussion in text
     FIG. 5.—Density-sensitive line ratios for Ar XII and Ca XIV

Full image (53kb) | Discussion in text
     FIG. 6.—Density-sensitive line ratios for Ar XIII and Ca XIII

TABLES

TABLE 1
A LIST OF HIGH-TEMPERATURE FORBIDDEN LINES PRESENT IN THE ACTIVE REGION CORONA
Measured
λ (Å)
Predicted
λ (Å) a
Ion Transition Intensity b
545.26... 545.21 Ca XIV 2s22p3 4S3/2–2s22p3 2P3/2 0.43
579.85... 579.83 Ca XIV 2s22p3 4S3/2–2s22p3 2P1/2 0.37
592.23 cP... … Fe XIX 2s22p4 3P2–2s22p4 1D2 …
648.68... 648.92 Ca XIII 2s22p4 3P1–2s22p4 1S0 0.29
656.69... 656.60 Ar XIII 2s22p23P1–2s22p2 1S0 0.29
670.34... 670.35 Ar XII 2s22p3 4S3/2–2s22p3 2P1/2 0.24
880.43... 880.35 Ca XIV 2s22p3 4S3/2–2s22p3 2D5/2 1.67
943.61... 943.70 Ca XIV 2s22p3 4S3/2–2s22p3 2D3/2 2.43
974.86P... 974.82 Fe XVIII 2s22p 2P3/2–2s22p 2P1/2 3.62
1018.87P... 1018.72 Ar XII 2s22p3 4S3/2–2s22p3 2D5/2 1.13
1033.04... 1033.2 Ni XV 3s23p2 3P1–3s23p2 1S0 1.19
1034.48... 1034.9 Ni XIV 3s23p3 4S3/2–3s23p3 2P3/2 1.91
1054.62P... 1054.69 Ar XII 2s22p3 4S3/2–2s22p3 2D3/2 0.31
1098.44... 1098.42 Ca XV 2s22p2 3P1–2s22p2 1D2 0.26
1118.08P... 1118.08 Fe XIX 2s22p4 3P2–2s22p4 3P1 0.17
1133.79... 1133.76 Ca XIII 2s22p4 3P2–2s22p4 1D2 4.95
1153.16P... 1153.14 Fe XVII 2s22p53s 3P1–2s22p53s 3P0 1.24
1174.65P... 1174.72 Ni XIV 3s23p3 4S3/2–3s23p3 2P1/2 1.53
1277.22P... 1277.23 Ni XIII 3s23p4 3P1–3s23p4 1S0 0.78
1291.61... 1291.2 Ca XIV 2s22p3 2D3/2–2s22p3 2P3/2 0.26
1330.54... 1330.37 Ar XIII 2s22p2 3P1–2s22p2 1D2 0.22
1375.96P... 1375.93 Ca XV 2s22p2 3P2–2s22p2 1D2 0.39

     NOTE.— P denotes "previously identified." See text.
     a Predicted wavelengths for argon, calcium, and iron transitions are from Edlén (1983, 1984, 1985); predicted wavelengths for Ni lines are from Kaufman & Sugar (1986).
     b Intensities are given in units of mW st-1 m-2 and are obtained from a single active region reference spectrum.
     c This line was observed in a different reference spectrum from the other lines, and therefore no intensity is given.

Image of typeset table | Discussion in text

TABLE 2
ENERGY LEVELS WITHIN THE C I GROUND CONFIGURATION (2s22p2) OF AR XIII AND CA XV

ENERGY
(cm-1)
LEVEL Ar XIII Ca XV
3P0... 0.0 0.0
3P1... 9859 a 17555 a
3P2... 21859 a 35917 a
1D2... 85016 108593
1S0... 162138 (197648) a

     a Energy levels are from Edlén (1985). Numbers in parentheses are calculated values.

Image of typeset table | Discussion in text

TABLE 3
ENERGY LEVELS WITHIN THE N I GROUND CONFIGURATION (2s22p3) IN AR XII AND CA XIV
Level Energy
(cm-1)
Ar XII Ca XIV
4S3/2... 0.0 0.0
2D3/2... 94821 105976
2D5/2... 98146 113581
2P1/2... 149178 172458
2P3/2... (154050) a 183399

     a Energy levels are from Edlén (1984). Numbers in parentheses are calculated values.

Image of typeset table | Discussion in text

TABLE 4
ENERGY LEVELS WITHIN THE O I GROUND CONFIGURATION (2s22p4) IN CA XIII
Level Energy
(cm-1)
3P2... 0.0
3P1... 24465 a
3P0... 28880 a
1D2... 88200
1S0... 178624

     a Energy levels are from Edlén (1983).

Image of typeset table | Discussion in text

Kepler's undiscovered symmetry of space and time

Kepler was convinced that God had created the Universe in accordance with some perfect geometrical principle

Published on Dec 14, 2013
Kepler was convinced that God had created the Universe in accordance with some perfect geometrical principle! But when he observed the motion of the planets he found that they move in elliptical orbits with speeds that vary relative to their distance from the Sun. As the planet moves along its path, it sweeps out an equal area segments in an equal time. So there is a form of geometrical symmetry, but the symmetry seems to be broken by the shape of the elliptical orbit. This video explains an artist theory on the physics of 'time' as a physical process. In this theory if the planets orbits were circular there would be no variation in speed and we would have perfect symmetry in movement space and time. This is because objects just free-fall towards the greatest energy because it has the greatest time dilation. The time dilation formed by the Sun is spherical therefore a planet in circular orbit will not encounter a gravitational difference that is formed by time dilation.
These are links to mainstream physics videos that are relative to this theory:
This video highlights the spherical geometry of light when it is not effected by gravity: 'ScienceCasts Strange Flames on the International Space Station'
http://www.youtube.com/watch?v=BxxqCL...
This video explains how light as an electromagnetic wave is linked to Relativity: 'How Special Relativity Makes Magnets Work'
http://www.youtube.com/watch?v=1TKSfA...
This video explains the spherical geometry or symmetry of the electron. In Quantum Atom Theory this symmetry is formed of a photon electron coupling or magnetic dipole moment: 'Spherical Electron - Sixty Symbols'
http://www.youtube.com/watch?v=yYZhNB...

Nano Letters

Nano Letters

Nano Letters is a monthly peer-reviewed scientific journal published by the American Chemical Society. It was established in January 2001. The two editors-in-chief are A. Paul Alivisatos (University of California, Berkeley) and Charles M. Lieber (Harvard University). The 2010 impact factor for Nano Letters is 12.219, according to the Journal Citation Reports. The focus of the journal is rapid dissemination of selected elements regarding fundamental, original research reports on all topics related to the theory and practice of nanoscience and nanotechnology and their subdisciplines. Physical, chemical, and biological phenomena related to nanoscience and nanotechnology are part of this focus. Furthermore nanoscale materials science is also included, focusing on processes and applications of structures at this size. Subject coverage encompasses the following: Materials that are synthesized and processed by physical, chemical, and biological methods. The classes of these materials are organic, inorganic, and hybrid. Furthermore, these processes are subjects of modeling and simulation. Specifically these process range from synthesis to assembly, along with relevant interactions. Also of
Publisher
American Chemical Society
Country
United States
History
2001–present
Impact factor
12.219 (2010)

Sunday, May 3, 2015

the jews put obama in power to kill all the christians and muslms


Obama's Unforgivable Betrayal

The president's nuclear accommodation of radical Islamist theocrats threatens Israel's survival.

President Barack Obama walks out to speak in the Rose Garden of the White House in Washington, Thursday, April 2, 2015, about the breakthrough in the Iranian nuclear talks.
Accommodating Iran and risking Israel's future
By + More
Never! Never would Iran be allowed to have a nuclear weapon. That was the pledge of the Clinton and Bush administrations. Not only that. “Never” was the purpose of 191 nations in agreeing to the Nuclear Non-Proliferation Treaty. It came into force in 1970 to save the planet from destroying itself and all human life. Hence the near universal agreement, a unique adherence for an arms control measure.
But the story since then is maddening and ominous. One of the parties to the treaty was Iran, and Iran has been in almost continuous noncompliance with the treaty it agreed to.
Flash forward to the Obama administration. Now the president is no longer trying to stop Iran from going nuclear. “Never” has been slimmed down to 13 years – at best! The Iranians have secured enough nuclear fuel to make the first generation bomb small enough to be dropped from a transport plane. The former International Atomic Energy Agency inspector, Olli Heinonen, reckons the proposed agreement from the Lausanne talks leaves Iran “a threshold breakout nuclear state for the next 10 years.” But we may have only the mirage of an agreement since Ayatollah Ali Khamenei and his associates are producing tons of ambiguity about what was agreed – and on our side, where unity is essential in dealing with a very slippy adversary, there are troubling discrepancies between the French and U.S. understandings.
Just look at the wriggles and evasions since Lausanne. President Barack Obama said the sanctions would be lifted only after Iran has delivered on its commitments. Supreme Leader Khamenei and President Hassan Rouhani draw new red lines. They insist on the immediate removal of sanctions on agreement; they reject monitoring of Iran’s military sites and have the nerve to say its subversion – assistance to “resistance” groups – will continue.
Yet the sanctions that took years to put in place are being removed almost immediately, unlinked to a change in Iran’s behavior. The symmetry is grim: The Iranians walk away from long-standing commitments and the Americans compromise on long-standing demands.
Obama had previously stated that “the deal we’ll accept” with Iran “is that they end their nuclear program” and abide by the U.N. resolutions that have been in place. Yet more enrichment will continue with 5,000 centrifuges per decade and all restraints will end in 15 years.
That is the key. By making a breakout time the central measure by which to judge the effectiveness, the administration has made verification the most important part of the agreement. We must be in a position to show that we can detect what the Iranians are doing and when they are doing it. The IAEA inspectors must have access to declared and undeclared sites. The artificial deadline the administration imposed has had the perverse effect of pressuring Obama and Secretary of State John Kerry, and not the Iranian government, to make concessions. On almost every key issue, the Iranians won the day as the Obama administration folded. The entire infrastructure of the Iranian nuclear weapons program remains intact.
The Associated Press
Why is Kerry, not Iran, making concessions in nuclear deal negotiations?
There is no way to reconcile Obama’s acceptance of Iran as a threshold nuclear state with a safe fate for Israel. Thus the view overwhelmingly shared by Israelis that he is risking the Jewish state’s future. A deal based on this framework after all would threaten the survival of Israel. Obama has broken with Israel on an existential and unforgivable level. When Obama finally tightened the sanctions forcing Iran to the table, he surrendered, especially on the issue of centrifuges that Iran has developed. Perhaps Obama can afford a bad deal because he has a year and a half left of his presidency. But the people in the Middle East have to live with the consequences of Obama’s agreement with Iran long after he is gone. For that is when the bulk of the nuclear deal with the world powers will be in effect.
Obama deliberately wrote off the inconvenient view of the country that is most endangered, Israel. He accommodated radical Islamist theocrats when he should have insisted on the opposite, that the survival of Israel is non-negotiable. In effect, he betrayed the trust of the Jewish state. And it is not just Israel that opposes Obama’s deal. The Arab leaders, especially our closest friends, Saudi Arabia and Egypt, have made clear they share Israel’s view.
Linda Chavez asks whether any of our allies even trust our word any longer? Why should they when the president failed to live up to promises, for example, to stop Russian aggression in Ukraine, or to keep the murderous Assad regime from killing Syrian civilians. The Iranian deal is more capitulation to those who threaten U.S. national security. Iran will even get an immediate economic boost when we lift sanctions, which will strengthen a regime that is already ascendant as a regional power.
Obama has regularly tried to oversell Americans on this issue. When he became president, Iran had “thousands of centrifuges” which now would be cut down to around 6,000. In fact, according to the New York Post, in 2008 Iran only had 800 centrifuges. It was on Obama’s watch, and because of his perceived weakness, that Iran accelerated its nuclear program. Then, the president asserted that all of Iran’s “paths” to developing a nuclear arsenal would be blocked. Yet, he still acknowledged what is now the common perception that Iran might still be able to build a bomb in just a year.
The president offers false choices between something like this deal and U.S. involvement in another ground war in the Middle East. Why does he not acknowledge the third choice is to force Iran to behave: wider sanctions, diplomatic action and proximity pressures to force Iran to abide by six U.N. resolutions?
In fact, to prevent Iran from obtaining nuclear weapons capability, the U.S. must impose the most stringent possible limits on Iran’s ability to produce fissile material. It means permitting Iran only a civilian nuclear power program without enrichment facilities or capabilities. This must be joined with a strict and comprehensive inspection regime underpinned by credible and concrete promises to punish noncompliance. Such a deal must extend as long as the U.S. and its partners believe Iran retains its nuclear weapons ambition, which will threaten its neighbors, and remains the unsettling force in the Middle East.
But none of Iran’s nuclear facilities, including the Fordow center will be closed, as The Washington Post noted. Not one of the country’s 19,000 centrifuges will be dismantled. Tehran’s existing pile of enriched uranium will be “reduced” but not necessarily shipped out of the country. In effect, then, Iran’s nuclear infrastructure will remain intact even though some of it will be mothballed for 10 years. But when the accord lapses the Islamic Republic will instantly become a threshold nuclear state.
Most upsetting is that even with much greater restriction the deal would not be permanent but instead one or more sunset clauses whereby all limits would ultimately be lifted.
Congress fears it has no substantive input, which means a deal would be implemented without its consent. The vote and voice of Congress is vital to the credibility and durability of a final deal that would be acceptable to the U.S. and not just to this administration.
The Senate Foreign Relations Committee understands that breakout time is crucially related to the size of Iran’s stockpile of fissile material. How much of its existing stockpile would Iran be required to ship out of the country? It has reneged on one deal and will try to do it on another if it is allowed to continue its efforts to increase the efficiency of its operating centrifuges. We need prohibitions on such activity, which would also include bans on any and all work on centrifuges other than those currently installed or operated, as well as clear restrictions on when, where, why and how Iran could replace the installed centrifuges.
What would an acceptable deal look like? We need an end to all research and development activity on advanced centrifuges in Iran; a significant decrease in the number of centrifuges that are operational or become operational if Iran breaks the agreement and decides to build a bomb; the closing of the Fordow facility as an enrichment site, even if enrichment is suspended there; an agreement to ship Iran’s stockpile of enriched uranium out of the country; a commitment to scale back its nuclear programs significantly for 10 to 15 years and to accept intense international inspections; a willingness to limit enrichment of uranium at its Natanz facility to a level needed only for civilian purposes; to cut back installed centrifuges by about two-thirds, while converting Fordow into a center for peaceful research and foregoing enriching uranium there for at least 15 years; as well as modifying its Arak heavy-water reactor to render it incapable of producing plutonium for a bomb.
Limits on when, where, why and how Iran would replace centrifuges during a breakout time would be crucial to preventing Iran from developing more efficient centrifuges for use immediately after an agreement expires. Iran believes it can continue to use the Fordow underground uranium enrichment plant for developing centrifuges, while the U.S. says no enrichment could take place there for 15 years.
The United States should stand by its original demands to shut down the facility altogether with the purpose of limiting total output of Iran’s enrichment facilities to its current capability. That would prevent it from cutting breakout times with the flip of a switch if it chooses to renege on the deal. The next few months will be nothing less than a supreme test of our skill and our resolve and give the Obama administration the opportunity to manage a fundamental change that improperly handled would threaten American allies and the United States itself.