Patent Number: 
Section: claims

1. A laser-plasma-based acceleration system comprising:a focusing element;a laser pulse emission source configured and disposed to direct a laser beam to the focusing element to enable emission of a laser beam such that the laser pulses transform into a focused beam defining a longitudinal center line axis; and a chamber defining a nozzle having a throat and an exit orifice, the nozzle configured and disposed to enable emission of a critical density range gas jet from the exit orifice of the nozzle, for laser wavelengths ranging from ultraviolet to the mid-infrared, the critical density range gas jet exiting the exit orifice of the nozzle and defining a longitudinal center line axis that intersects the longitudinal center line axis of the focused beam at an angle,wherein the focused beam intersects the critical density range gas jet in proximity to the exit orifice of the nozzle to define a point of intersection between the focused beam and the critical density range gas jet,wherein, in intersection with the critical density range gas jet, the pulsed focused beam drives a laser plasma wakefield relativistic electron beam, andwherein the plasma wakefield relativistic electron beam energy is at least 0.5 MeV with charge electron bunches greater than 10 femto coulombs wherein the focused laser energy is less than or equal to 10 mJ. 2. The laser-plasma-based acceleration system according to claim 1, wherein the critical density range is an electron density Ne that is defined to be 0.1 Ncr <Ne<3Ncr, where the critical density is Ncr=1.12×1021 λ−2 (cm−3), where λ is the laser wavelength in microns (μm). 3. The laser-plasma-based acceleration system according to claim 1, wherein the critical density range gas jet generates electron densities Ne, upon laser interaction, in the approximate range 0.1 Ncr to 3Ncr. 4. The laser-plasma-based acceleration system according to claim 1, wherein for a laser wavelength of λ=0.8 μm of the focused beam, the critical density range includes 2×1020 cm−3 to 5×1021 cm−3. 5. The laser-plasma-based acceleration system according to claim 1, wherein the critical density range of the critical density range gas jet is formed by cryogenic cooling of a gas source in fluid communication with the chamber defining the nozzle. 6. The laser-plasma-based acceleration system according to claim 1, wherein the laser wavelengths ranging from ultraviolet to mid-infrared include wavelengths ranging from 0.3 μm to 2 μm. 7. The laser-plasma-based acceleration system according to claim 1, wherein the laser pulses are at an energy level up to and including 20 mJ. 8. A method of laser-plasma-based acceleration comprising:directing a laser beam to a focusing element to enable emission of a laser beam such that the laser pulses transform into a focused beam defining a longitudinal center line axis;emitting a critical density range gas jet from an exit orifice of a nozzle for laser wavelengths ranging from ultraviolet to mid-infrared;causing the focused beam to intersect the critical density range gas jet in proximity to the exit orifice of the nozzle to define a point of intersection between the focused beam and the critical density range gas jet,wherein, in intersection with the critical density range gas jet, the pulsed focused beam drives a laser plasma wakefield relativistic electron beam, andwherein the plasma wakefield relativistic electron beam energy is at least 0.5 MeV with charge electron bunches greater than 10 femto coulombs wherein the focused laser energy is less than or equal to 10 mJ. 9. The method of laser-plasma-based acceleration according to claim 8, wherein the emitting a critical density range gas is emitting a critical density range gas at a critical electron density that is an electron density Ne that is defined to be 0.1 Ncr <Ne<3Ncr, where the critical density is Ncr=1.12×1021λ−2 (cm−3), where λ is the laser wavelength in microns (μm). 10. The method of laser-plasma-based acceleration according to claim 8, wherein the critical density range gas jet generates electron densities Ne, upon laser interaction, in the approximate range 0.1 Ncr to 3Ncr. 11. The method of laser-plasma-based acceleration according to claim 8, wherein for a laser wavelength of λ=0.8 μm of the focused beam, the critical density range includes 2×1020 cm−3 to 5×1021 cm−3. 12. The method of laser-plasma-based acceleration according to claim 8, wherein the critical density range of the critical density range gas jet is formed by cryogenic cooling of a gas source in fluid communication with the chamber defining the nozzle. 13. The method of laser-plasma-based acceleration according to claim 8, wherein the laser wavelengths ranging from ultraviolet to mid-infrared include wavelengths ranging from 0.3 μm to 2 μm. 14. The method of laser-plasma-based acceleration according to claim 8, wherein the laser pulses are at an energy level up to and including 20 mJ. 15. The laser-plasma-based acceleration system according to claim 1, wherein the laser pulse repetition rate is 1 kHz. 16. The method of laser-based acceleration according to claim 8, wherein the laser pulses transform into a focused beam defining a longitudinal center line axis at a repetition rate of 1 kHz. 17. A laser-plasma-based acceleration system comprising:a focusing element;a laser pulse emission source configured and disposed to direct a laser beam to the focusing element to enable emission of a laser beam such that the laser pulses transform into a focused beam defining a longitudinal center line axis; and a chamber defining a nozzle having a throat and an exit orifice, the nozzle configured and disposed to enable emission of a critical density range gas jet from the exit orifice of the nozzle, for laser wavelengths ranging from ultraviolet to the mid-infrared, the critical density range gas jet exiting the exit orifice of the nozzle and defining a longitudinal center line axis that intersects the longitudinal center line axis of the focused beam at an angle,wherein the focused beam intersects the critical density range gas jet in proximity to the exit orifice of the nozzle to define a point of intersection between the focused beam and the critical density range gas jet,wherein, in intersection with the critical density range gas jet, the pulsed focused beam drives a laser plasma wakefield relativistic electron beam, andwherein the plasma wakefield relativistic electron bunch energy is at least 0.5 MeV with charge greater than 10 femto coulombs wherein the focused laser energy is less than or equal to 10 mJ. 18. The laser-plasma-based acceleration system according to claim 17, wherein the laser pulse repetition rate is 1 kHz. 19. A method of laser-plasma-based acceleration comprising:directing a laser beam to a focusing element to enable emission of a laser beam such that the laser pulses transform into a focused beam defining a longitudinal center line axis;emitting a critical density range gas jet from an exit orifice of a nozzle for laser wavelengths ranging from ultraviolet to mid-infrared;causing the focused beam to intersect the critical density range gas jet in proximity to the exit orifice of the nozzle to define a point of intersection between the focused beam and the critical density range gas jet,wherein, in intersection with the critical density range gas jet, the pulsed focused beam drives a laser plasma wakefield relativistic electron beam, andwherein the plasma wakefield relativistic electron bunch energy is at least 0.5 MeV with charge greater than 10 femto coulombs wherein the focused laser energy is less than or equal to 10 mJ. 20. The method of laser-based acceleration according to claim 19, wherein the laser pulses transform into a focused beam defining a longitudinal center line axis at a repetition rate of 1 kHz.