Dielectronic recombination measurements for the Li-like ions:<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msup><mml:mrow><mml:mi mathvariant="normal">B</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn><mml:mo>+</mml:mo></mml:mrow></mml:msup></mml:mrow></mml:math>,<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msup><mml:mrow><mml:mi mathvariant="normal">C</mml:mi></mml:mrow><mml:mrow><mml:mn>3</mml:mn><mml:mo>+</mml:mo></mml

Pf, Dittner; Datz, S.; Pd, Miller; Pepmiller, P.L.; Cm, Fou

doi:10.1103/physreva.35.3668

Cited by 39 publications

(11 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Experiments have also been performed [7][8][9][10][11]. The agreement between the experiments and theory is qualitative, with the size of the enhancement being in rough agreement.…”

mentioning

confidence: 81%

See 1 more Smart Citation

Enhanced Dielectronic Recombination in Crossed Electric and Magnetic Fields

Robicheaux

Pindzola

1997

Phys. Rev. Lett.

View full text Add to dashboard Cite

The dependence of the dielectronic recombination cross section on crossed electric and magnetic fields is described. The enhancement of this cross section due to a static electric field is further increased when a magnetic field is added perpendicular to the electric field. Calculation of this field induced enhancement is presented for a realistic atomic model, and the mechanism for the enhancement is discussed.[S0031-9007 (97)04035-0] PACS numbers: 34.80.Kw, 32.60. + i, 32.80.DzPhotorecombination is the inverse of photoionization and is the process by which a free electron simultaneously emits a photon and makes a transition to a bound state. It is the purpose of this paper to show that certain types of photorecombination processes can be greatly enhanced in static, crossed electric and magnetic fields. Besides being intrinsically interesting, this enhancement may affect the interpretation of recent experiments on photorecombination in static electric fields and affect the recombination rate in some tenuous astrophysical plasmas.Burgess and Summers [1] suggested that under some circumstances the dielectronic recombination (DR) rate could be enhanced due to angular momentum redistribution during three-body collisions. DR is photorecombination that proceeds through the capture of an electron by an ion in an autoionizing state; the incident electron induces a transition in the ion but loses so much energy it is captured into a resonance state. Before the electron can regain the energy from the core electrons and leave the ion, a photon is emitted and the electron is captured into a bound state. Jacobs et al. [2,3] showed that ᐉ redistribution of the autoionizing state due to plasma (electric) microfields can strongly enhance the DR rate.The prototypical example for studying field effects is the DR of a Li-like ion. The initial state is a free electron, and the ion is in the 1s 2 2s configuration. The autoionizing state is 1s 2 2pnᐉ. The system is stabilized by the 2p electron emitting a photon, leaving the system in the 1s 2 2snᐉ bound state. The physical reason for enhanced DR in a static field can be understood in a time dependent picture. The electron is initially captured in an nᐉ state while simultaneously exciting the core. If an electric field is on, the Rydberg state will precess into states of higher angular momentum. Since the autoionization rate rapidly decreases with angular momentum, this has the effect of making photon emission more probable.In the more traditional time independent picture, the contribution of a resonance r to the DR rate is proportional to G a,r G R,r ͑͞G a,r 1 G R,r ͒ (i.e., proportional to the probability to be captured into the state times the branching ratio for photon emission). The total photorecombination rate is proportional to the sum over all resonances r of G a,r G R,r ͑͞G a,r 1 G R,r ͒. [Each resonance is only counted once, but often the degeneracy of levels is utilized to simplify calculations. For example, in zero field, J and M are good quantum numbers so the resonance...

show abstract

“…Experiments have also been performed [7][8][9][10][11]. The agreement between the experiments and theory is qualitative, with the size of the enhancement being in rough agreement.…”

mentioning

confidence: 81%

“…There are also static magnetic fields present (180 G in Ref. [9], 24 G in Ref. [10], and 300 G in Ref.…”

mentioning

confidence: 99%

Enhanced Dielectronic Recombination in Crossed Electric and Magnetic Fields

Robicheaux

Pindzola

1997

Phys. Rev. Lett.

View full text Add to dashboard Cite

show abstract

“…For Be-like [6] and B-like [7] ions studied there, good agreement with theory could be imposed by adjusting the field to a reasonable magnitude. However, using a nearly identical apparatus configuration for the Li-like ions B 21 , C 31 , N 41 , and O 51 [8], 0031-9007͞97͞79(12)͞2233(4)$10.00 agreement with theory [9,10] could not be obtained with like fields, and in fact, fields required to obtain agreement were unrealistically large. An attempt was made at Harvard [11] using Li-like C 31 and a known applied field in an inclined-beams experiment to resolve the inconsistencies.…”

mentioning

confidence: 93%

Field Enhanced Dielectronic Recombination ofSi11+Ions

et al. 1997

View full text Add to dashboard Cite

The enhancement of dielectronic recombination by applied electric fields has been observed and measured for the first time in a wide range of controlled and measurable fields using multiply charged ions. The heavy ion storage ring CRYRING at Stockholm University was used to store a beam of Si 111 and collide it with a cold electron target. Rydberg resonances up to n 25 are resolved for both the 2p 3͞2 and 2p 1͞2 series. The observation of a substantial monotonic increase of the rate coefficient for the group of higher Rydberg states is in puzzling disagreement with theoretical calculations of electric field enhanced dielectronic recombination.[S0031-9007(97)04040-4]

show abstract

“…At present there are a few measurements of ionization cross sections for charge states up to q ;S + 50, * but direct measurements of electron-impact excitation (IE), dielectronic recombination (DR), and radiative recombination (RR) cross sections have been possible only for q ;S + 6 with use of the available techniques of crossed or merged beams. 2, 3 We have developed a new technique which, for the first time, makes it possible to measure all of these cross sections for highly charged ions. The technique consists of trapping ions inside an electron beam compressed to a density of order 2000 A/cm 2 .…”

mentioning

confidence: 99%

Measurement of electron-impact–excitation cross sections for very highly charged ions

et al. 1988

View full text Add to dashboard Cite

We report the first measurements of electron-impact-excitation cross sections for very highly charged ions (Ba 46+ ), and introduce a powerful new technique for studying these ions. Approximately 2xl0 4 Ba 46+ ions/cm were trapped inside the space charge of an -120-mA electron beam and their x-ray emission spectra observed with Si (Li) and Bragg-crystal-diffraction spectrometers. Cross sections for several /i™3 levels excited from the neonlike Ba 46+ ground state were measured relative to radiative recombination on the same ions.PACS numbers: 34.80.KwThe interaction of highly charged ions with electrons, as well as their spectroscopic properties, are important for the understanding of atomic structure in the highfield (high Z) limit where relativistic and QED effects are important. At present there are a few measurements of ionization cross sections for charge states up to q ;S + 50, * but direct measurements of electron-impact excitation (IE), dielectronic recombination (DR), and radiative recombination (RR) cross sections have been possible only for q ;S + 6 with use of the available techniques of crossed or merged beams. 2, 3 We have developed a new technique which, for the first time, makes it possible to measure all of these cross sections for highly charged ions. The technique consists of trapping ions inside an electron beam compressed to a density of order 2000 A/cm 2 . Cross sections are determined from x-ray spectroscopy of the trapped ions excited by the electron beam. Because the target ions are prepared in a single charge state and the electron beam is monoenergetic, it is possible to unravel all of the separate cross sections which contribute to x-ray emission.The method of successive ionization of ions trapped in an electron beam is also used in the electron-beam ion sources (EBIS) developed to provide highly charged ions for injection into accelerators. 1 There is one published observation of x rays from an EBIS (from DR on Ar 14+ ). 4 However, the EBIS sources have not proved suitable for x-ray spectroscopy of more highly charged ions. In contrast to the EBIS, our device uses a different and much smaller geometry which is optimized for x-ray spectroscopy. 5 In this Letter we describe our electronbeam ion trap and present measurements of the IE cross sections (relative to RR on the same ions) for several n =2 to n =3 transitions in the neonlike Ba 46+ ion.As shown schematically in Fig. 1, the ion trap consisted of a copper cylinder with an inside diameter of 10 mm in the central trap region and 3 mm at the ends. The electron beam, which follows the central magnetic-field line of the superconducting Helmholtz coils, was injected vertically from a Pierce gun. The beam was adiabatically compressed in the Helmholtz-coil field. The electron currents used ranged from 60 to 120 mA, and the beam radius at the peak magnetic field of 3 T was roughly 35 lira.The electron-ion interaction energy was determined by the output voltage of a precision high-voltage regulator that biased the drift tube. Because of th...

show abstract

Dielectronic recombination measurements for the Li-like ions:B2+,C3+

Cited by 39 publications

References 10 publications

Enhanced Dielectronic Recombination in Crossed Electric and Magnetic Fields

Enhanced Dielectronic Recombination in Crossed Electric and Magnetic Fields

Field Enhanced Dielectronic Recombination ofSi11+Ions

Measurement of electron-impact–excitation cross sections for very highly charged ions

Contact Info

Product

Resources

About