Comparison of quantum-mechanical and classical trajectory calculations of cross sections for ion-atom impact ionization of negative and positive ions for heavy-ion fusion applications

Kaganovich, Igor; Startsev, Edward A.; Davidson, Ronald C.

doi:10.1103/physreva.68.022707

Cited by 13 publications

(10 citation statements)

References 19 publications

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“…In most cases both approximations give similar results [2,3]. However, for fast projectile velocities and low-ionization potentials, the classical approach is not valid and can overestimate the stripping cross-sections by neutral atoms by an order-of-magnitude [4].…”

Section: Discussionmentioning

confidence: 50%

“…[7]. However, the correct quantum mechanical calculations show a large difference between the stripping cross-sections by neutral atoms and fully stripped ions as targets, because classical mechanics overestimates the probability of ionization, presuming that the electron can be located at prescribed impact parameter [4].…”

Section: Article In Pressmentioning

confidence: 96%

“…At high energies, classical mechanics overestimates the probability of ionization, presuming that the electron can be located at a prescribed impact parameter (see details in Ref. [4]). …”

Section: Article In Pressmentioning

confidence: 99%

“…In most cases, both approximations give similar results. However, for fast projectile velocities and low ionization potentials, the classical approach, is not valid and can overestimate the stripping crosssections by neutral atoms by an order of magnitude [4]. Therefore, a hybrid approach that automatically chooses between the Born approximation and the classical mechanics approximation depending on the parameters of the collision [5] has been developed.…”

Section: Introductionmentioning

confidence: 99%

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Ionization cross-sections for ion–atom collisions in high-energy ion beams

Kaganovich

Startsev

Davidson

et al. 2005

Nuclear Instruments and Methods in Physics Research Section A:

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Section: Discussionmentioning

confidence: 50%

Section: Article In Pressmentioning

confidence: 96%

“…At high energies, classical mechanics overestimates the probability of ionization, presuming that the electron can be located at a prescribed impact parameter (see details in Ref. [4]). …”

Section: Article In Pressmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Ionization cross-sections for ion–atom collisions in high-energy ion beams

Kaganovich

Startsev

Davidson

et al. 2005

Nuclear Instruments and Methods in Physics Research Section A:

Self Cite

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“…Followed were theoretical approaches to unsolved data especially for nearterm experiments in HIF especially multi-electron stripping. Among various approaches, CTMC method is simpler and can yield results close to quantum mechanical calculations [1,[8][9][10][11][12][13][14][15]. That's why we use CTMC approach here in the calculation of ionization cross sections.…”

mentioning

confidence: 99%

Study of Ion Stripping and Charge Exchange for Heavy Ion Fusion

Miley

Momota

et al. 2005

21st IEEE/NPS Symposium on Fusion Engineering SOFE 05

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To accurately model transport in the heavy ion fusion chamber, it is necessary to know the evolution of beam charge state due to ionization or recombination. At present there is no accurate or complete information for electron loss and capture from these fast, low-charge heavy ions, and the theoretical model in the simulation codes, such as LSP is not accurate enough to describe the processes, especially multi-electron ionizations. Thus, it is very important to explore better theoretical approaches to calculate cross sections of multi-electron losses especially ion stripping, charge exchange for near-term and driver scale HIF research. Based on the investigation of different approaches on the heavy ion-atom collisions, with emphasis on the features related with low-charged heavy ions, especially multi-electron processes and correlation effects, an improved classic trajectory Monte Carlo simulation model will be set up to solve the n-body ion-atom ionization problem in HIF's interest. The calculation results will be benchmarked with the data obtained through finished experiments from the literature as well. Finally, the improved code will be implemented into LSP code as a subroutine to become an integral part of the code. In current stage, a subroutine with a database of typical ionization stripping cross sections and change exchange for low-charge-state, heavy ions mainly in the experimental energy level will be developed for LSP code to serve ongoing experiments and simulations in current heavy ion beam fusion project, which is shown in this paper. More data including for the energy in drive scale can be integrated into the subroutine in the future expecting to be used in HIF and High Energy Density Physics as well.

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Experimental evaluation of a negative-ion source for a heavy-ion fusion negative-ion driver

Grisham

Hahto

Kwan

et al. 2005

Nuclear Instruments and Methods in Physics Research Section A:

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Negative halogen ions have recently been proposed as a possible alternative to positive ions for heavy ion fusion drivers because electron accumulation would not be a problem in the accelerator, and if desired, the beams could be photodetached to neutrals [1,2,3]. To test the ability to make suitable quality beams, an experiment was conducted at Lawrence Berkeley National Laboratory using chlorine in an RF-driven ion source. Without introducing any cesium (which is required to enhance negative ion production in hydrogen ion sources) a negative chlorine current density of 45 mA/cm 2 was obtained under the same conditions that gave 57 mA/cm 2 of positive chlorine, suggesting the presence of nearly as many negative ions as positive ions in the plasma near the extraction plane. The negative ion spectrum was 99.5% atomic chlorine ions, with only 0.5% molecular chlorine, and essentially no impurities. Although this experiment did not incorporate the type of electron suppression technology that is used in negative hydrogen beam extraction, the ratio of co-extracted electrons to Cl -was as low as 7 to 1, many times lower than the ratio of their mobilities, suggesting that few electrons are present in the near-extractor plasma. This, along with the near-equivalence of the positive and negative ion currents, suggests that the plasma in this region was mostly an ion-ion plasma. The negative chlorine current density was relatively insensitive to pressure, and scaled linearly with RF power. If this linear scaling continues to hold at higher RF powers, it should permit current densities of 100 mA/cm 2 , sufficient for present heavy ion fusion injector concepts. The effective ion temperatures of the positive and negative ions appeared to be similar and relatively low for a plasma source.

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Comparison of quantum-mechanical and classical trajectory calculations of cross sections for ion-atom impact ionization of negative and positive ions for heavy-ion fusion applications

Cited by 13 publications

References 19 publications

Ionization cross-sections for ion–atom collisions in high-energy ion beams

Ionization cross-sections for ion–atom collisions in high-energy ion beams

Study of Ion Stripping and Charge Exchange for Heavy Ion Fusion

Experimental evaluation of a negative-ion source for a heavy-ion fusion negative-ion driver

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