FEL2014 - List of Authors (van der Slot, P.J.M.)

Paper

Title

Page

MINERVA, a New Code to Model Free-Electron Lasers

408

H. Freund, P.J.M. van der Slot
CSU, Fort Collins, Colorado, USA
P.J.M. van der Slot
Mesa+, Enschede, The Netherlands

Simulation codes modelling the interaction of electrons with an optical field inside an undulator are an essential tool for understanding and designing free-electron lasers (FELs). As there exists a large variety of FELs ranging from long-wavelength oscillators using partial wave guiding to soft and hard x-ray FELs that are either seeded or starting from noise, a simulation code should be capable of modelling this huge variety of FEL configurations. A new code under development, named MINERVA, will be capable of modelling such a large variety of FELs. The code uses a modal expansion for the optical field, e.g., a Gaussian expansion for free-space propagation, and an expansion in waveguide modes for propagation at long wavelengths, or a combination of the two for partial guiding at THz frequencies. MINERVA uses the full Newton-Lorentz force equation to track the particles through the optical and magnetic fields. To allow propagation of the optical field outside the undulator and interact with optical elements, MINERVA interfaces with the optical propagation code OPC to model oscillators. Here we describe the main features of MINERVA and give various examples of its capabilities.

TUP021

Recent Updates to the Optical Propagation Code OPC

412

P.J.M. van der Slot, K.J. Boller
Mesa+, Enschede, The Netherlands
P.J.M. van der Slot
CSU, Fort Collins, Colorado, USA

Funding: This research is supported in part by Office of Naval Research Global, grant number N62909-10-1-7151
In order to understand and design free-electron lasers (FELs), simulation codes modeling the interaction of electrons with a co-propagating optical field in the magnetic field of an undulator are essential. However, propagation of the optical field outside the undulator is equally important for evaluation of the optical field at the location of the application or to model FEL oscillators. The optical propagation code OPC provides such capabilities and can interface with FEL gain codes like GENESIS 1.3, MEDUSA and MINERVA. Here we present recent additions and modifications to the code that (i) improves the speed of the code and (ii) extends the modeling capabilities. These include amongst other, inline diagnostics that results in considerable faster runtimes, the ability to convert from free-space modes to guided modes (currently only cylindrical waveguides), and the possibility to determine the spectrum at each transverse location. The latter opens the possibility to include dispersion in the optical propagation. Finally, work is underway to support HDF5 to remain compatible with the upcoming new release of GENESIS 1.3.

TUP021

Recent Updates to the Optical Propagation Code OPC

412

P.J.M. van der Slot, K.J. Boller
Mesa+, Enschede, The Netherlands
P.J.M. van der Slot
CSU, Fort Collins, Colorado, USA

Funding: This research is supported in part by Office of Naval Research Global, grant number N62909-10-1-7151
In order to understand and design free-electron lasers (FELs), simulation codes modeling the interaction of electrons with a co-propagating optical field in the magnetic field of an undulator are essential. However, propagation of the optical field outside the undulator is equally important for evaluation of the optical field at the location of the application or to model FEL oscillators. The optical propagation code OPC provides such capabilities and can interface with FEL gain codes like GENESIS 1.3, MEDUSA and MINERVA. Here we present recent additions and modifications to the code that (i) improves the speed of the code and (ii) extends the modeling capabilities. These include amongst other, inline diagnostics that results in considerable faster runtimes, the ability to convert from free-space modes to guided modes (currently only cylindrical waveguides), and the possibility to determine the spectrum at each transverse location. The latter opens the possibility to include dispersion in the optical propagation. Finally, work is underway to support HDF5 to remain compatible with the upcoming new release of GENESIS 1.3.

WEA02

Free Electron Laser Oscillator: Short Pulses, Mode Locking, Harmonic Generation and Tapering

G. Dattoli, E. Sabia
ENEA C.R. Frascati, Frascati (Roma), Italy
S. Biedron, S.V. Milton
CSU, Fort Collins, Colorado, USA
V. Petrillo
Universita' degli Studi di Milano, Milano, Italy
P.J.M. van der Slot
Mesa+, Enschede, The Netherlands

In Free Electron Laser oscillators the growth of the intracavity laser power determines the most interesting aspects of the system dynamics. In the case of short pulses operation the system undergoes genuine mode-locking mechanisms, which provide a wealth of interesting phenomena associated with the possibility of generating very short pulses. We explore the mechanisms of superradiance in FEL operating in the over-saturated regime and analyze the emerging short pulse structures and the relevant physical meaning. We also explore the pulse shape of the higher order harmonics generated in this regime and the possibility of modelling the pulse width and power by suitable combination of cavity length control and of undulator tapering.

Slides WEA02 [13.588 MB]

Paper	Title	Page
TUP020	MINERVA, a New Code to Model Free-Electron Lasers	408
	H. Freund, P.J.M. van der Slot CSU, Fort Collins, Colorado, USA P.J.M. van der Slot Mesa+, Enschede, The Netherlands
	Simulation codes modelling the interaction of electrons with an optical field inside an undulator are an essential tool for understanding and designing free-electron lasers (FELs). As there exists a large variety of FELs ranging from long-wavelength oscillators using partial wave guiding to soft and hard x-ray FELs that are either seeded or starting from noise, a simulation code should be capable of modelling this huge variety of FEL configurations. A new code under development, named MINERVA, will be capable of modelling such a large variety of FELs. The code uses a modal expansion for the optical field, e.g., a Gaussian expansion for free-space propagation, and an expansion in waveguide modes for propagation at long wavelengths, or a combination of the two for partial guiding at THz frequencies. MINERVA uses the full Newton-Lorentz force equation to track the particles through the optical and magnetic fields. To allow propagation of the optical field outside the undulator and interact with optical elements, MINERVA interfaces with the optical propagation code OPC to model oscillators. Here we describe the main features of MINERVA and give various examples of its capabilities.

TUP021	Recent Updates to the Optical Propagation Code OPC	412
	P.J.M. van der Slot, K.J. Boller Mesa+, Enschede, The Netherlands P.J.M. van der Slot CSU, Fort Collins, Colorado, USA
	Funding: This research is supported in part by Office of Naval Research Global, grant number N62909-10-1-7151 In order to understand and design free-electron lasers (FELs), simulation codes modeling the interaction of electrons with a co-propagating optical field in the magnetic field of an undulator are essential. However, propagation of the optical field outside the undulator is equally important for evaluation of the optical field at the location of the application or to model FEL oscillators. The optical propagation code OPC provides such capabilities and can interface with FEL gain codes like GENESIS 1.3, MEDUSA and MINERVA. Here we present recent additions and modifications to the code that (i) improves the speed of the code and (ii) extends the modeling capabilities. These include amongst other, inline diagnostics that results in considerable faster runtimes, the ability to convert from free-space modes to guided modes (currently only cylindrical waveguides), and the possibility to determine the spectrum at each transverse location. The latter opens the possibility to include dispersion in the optical propagation. Finally, work is underway to support HDF5 to remain compatible with the upcoming new release of GENESIS 1.3.

TUP021	Recent Updates to the Optical Propagation Code OPC	412
	P.J.M. van der Slot, K.J. Boller Mesa+, Enschede, The Netherlands P.J.M. van der Slot CSU, Fort Collins, Colorado, USA
	Funding: This research is supported in part by Office of Naval Research Global, grant number N62909-10-1-7151 In order to understand and design free-electron lasers (FELs), simulation codes modeling the interaction of electrons with a co-propagating optical field in the magnetic field of an undulator are essential. However, propagation of the optical field outside the undulator is equally important for evaluation of the optical field at the location of the application or to model FEL oscillators. The optical propagation code OPC provides such capabilities and can interface with FEL gain codes like GENESIS 1.3, MEDUSA and MINERVA. Here we present recent additions and modifications to the code that (i) improves the speed of the code and (ii) extends the modeling capabilities. These include amongst other, inline diagnostics that results in considerable faster runtimes, the ability to convert from free-space modes to guided modes (currently only cylindrical waveguides), and the possibility to determine the spectrum at each transverse location. The latter opens the possibility to include dispersion in the optical propagation. Finally, work is underway to support HDF5 to remain compatible with the upcoming new release of GENESIS 1.3.

WEA02	Free Electron Laser Oscillator: Short Pulses, Mode Locking, Harmonic Generation and Tapering
	G. Dattoli, E. Sabia ENEA C.R. Frascati, Frascati (Roma), Italy S. Biedron, S.V. Milton CSU, Fort Collins, Colorado, USA V. Petrillo Universita' degli Studi di Milano, Milano, Italy P.J.M. van der Slot Mesa+, Enschede, The Netherlands
	In Free Electron Laser oscillators the growth of the intracavity laser power determines the most interesting aspects of the system dynamics. In the case of short pulses operation the system undergoes genuine mode-locking mechanisms, which provide a wealth of interesting phenomena associated with the possibility of generating very short pulses. We explore the mechanisms of superradiance in FEL operating in the over-saturated regime and analyze the emerging short pulse structures and the relevant physical meaning. We also explore the pulse shape of the higher order harmonics generated in this regime and the possibility of modelling the pulse width and power by suitable combination of cavity length control and of undulator tapering.
	Slides WEA02 [13.588 MB]